SC TO-T/A

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE TO

Tender Offer Statement under Section 14(d)(1) or 13(e)(1)

of the Securities Exchange Act of 1934

(Amendment No. 12)

LAFARGE NORTH AMERICA INC.

(Name of Subject Company (issuer))

EFALAR INC.
a wholly owned subsidiary of
LAFARGE S.A.

(Names of Filing Persons (Offerors))

COMMON STOCK, PAR VALUE $1.00 PER SHARE

(Title of Class of Securities)

505862-10-2

(CUSIP Number of Class of Securities)

Laurent Alpert
Cleary Gottlieb Steen & Hamilton LLP
One Liberty Plaza
New York, New York 10006
Telephone: (212) 225-2340

(Name, address, and telephone numbers of person authorized

to receive notices and communications on behalf of filing persons)

Calculation of Filing Fee

Transaction valuation*	Amount of filing fee**
$3,326,185,039.50	$	355,901.80

*

Estimated for purposes of calculating the amount of filing fee only. The calculation assumes the purchase of all outstanding shares of common stock, par value $1.00 per share, of Lafarge North America Inc., a Maryland corporation, other than the shares owned by Lafarge S.A. and its subsidiaries, at a purchase price of $85.50 per share, net to the seller in cash. As of May 13, 2006 there were 79,111,237 shares of common stock outstanding, of which 40,208,488 shares are owned by Lafarge S.A. and its subsidiaries. As a result, this calculation assumes the purchase of 38,902,749 shares.

**

the amount of filing fee is calculated in accordance with Rule 240.0-11 of the Securities Exchange Act of 1934, as amended, and Fee Rate Advisory No. 5 for fiscal year 2006 issued by the Securities and Exchange Commission on November 23, 2005. Such fee equals 0.010700% of the transaction value.

þ Check the box if any part of the fee is offset as provided by Rule 0-11(a)(2) and identify the filing with which the offsetting fee was previously paid. Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing.

1.	Amount Previously Paid:	$255,446.94	2.	Amount Previously Paid:	$23,841.71
	Form or Registration No.:	Schedule TO-T		Form or Registration No.:	Schedule TO-T/A
	Filing Party:	Lafarge S.A.		Filing Party:	Lafarge S.A.
	Date Filed:	February 21, 2006		Date Filed:	April 7, 2006
3.	Amount Previously Paid:	$28,383.43
	Form or Registration No.:	Schedule TO-T/A
	Filing Party:	Lafarge S.A.
	Date Filed:	May 1, 2006

o Check the box if the filing relates solely to preliminary communications made before the commencement of a tender offer.

Check the appropriate boxes below to designate any transactions to which the statement relates:

þ third-party tender offer subject to Rule 14d-1.

o issuer tender offer subject to Rule 13e-4.

þ going-private transaction subject to Rule 13e-3.

o amendment to Schedule 13D under Rule 13d-2.

_{SEC2559 (6-05)} Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.

Check the following box if the filing is a final amendment reporting the results of the tender offer: þ

     This Amendment No. 12 amends and supplements the Tender Offer Statement and Rule 13E-3 Transaction Statement filed under cover of Schedule TO (this “Schedule TO”) with the Securities and Exchange Commission (“SEC”) on February 21, 2006, by Lafarge S.A., a French société anonyme (“Parent”) and Efalar Inc., a Delaware corporation and direct, wholly-owned subsidiary of Parent (“Purchaser”). This Schedule TO relates to the amended offer by Purchaser to purchase all outstanding shares of common stock, par value $1.00 per share (“Common Shares”), of Lafarge North America Inc., a Maryland corporation (the “Company”) not owned by Parent and its subsidiaries, at a purchase price of $85.50 per Common Share, net to the seller in cash, upon the terms and subject to the conditions set forth in the Offer to Purchase, dated February 21, 2006, the First Supplement to the Offer to Purchase, dated April 7, 2006, the Second Supplement to the Offer to Purchase, dated May 1, 2006 (the “Second Supplement”), in each case as amended by amendments to the Schedule TO filed by Parent with the SEC prior to the date hereof, and the related second revised Letter of Transmittal (which, as amended or supplemented from time to time, collectively constitute the “Second Amended Offer”).

Item 12. Exhibits.

(a)(1)(xxxv)     Press Release Issued by Lafarge S.A. on May 15, 2006.

Item 13. Information Required by Schedule 13E-3

     Item 11. Interest in Securities of the Subject Company.

     At 12:00 midnight, New York City time, on Friday, May 12, 2006, the Second Amended Offer expired and Parent accepted for payment all Common Shares tendered. Based on the report by the depositary, Purchaser acquired approximately 34,253,627 Common Shares (including guaranteed deliveries) pursuant to the Second Amended Offer.

     Concurrently with the expiration of the Second Amended Offer, Parent’s offer, through another of its wholly-owned subsidiaries, to acquire all of the exchangeable preference shares of Lafarge Canada Inc., a wholly-owned subsidiary of the Company, at the same per share price that was offered for the Common Shares (the “EPS Offer”) expired and Parent accepted for payment all exchangeable preference shares tendered. Based on the report by the depositary, approximately 444,230 exchangeable preference shares (including guaranteed deliveries) were acquired in the EPS Offer.

     The tendered Common Shares and the tendered exchangeable preference shares combined with the Common Shares already owned by Parent through its wholly-owned subsidiaries, represent approximately 92.37% of the outstanding Common Shares and exchangeable preference shares taken together as a single class.

     The full text of the press release announcing completion of the Second Amended Offer and EPS Offer is attached as Exhibit (a)(1)(xxxv) hereto and incorporated herein by reference.

SIGNATURES

After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

	LAFARGE S.A.
	By: /s/ Michel Bisiaux
	Michel Bisiaux Corporate Secretary
	EFALAR INC.
	By: /s/ Michel Bisiaux
	Michel Bisiaux Secretary
Dated: May 15, 2006

EXHIBIT INDEX

EXHIBIT	DESCRIPTION
(a)(1)(xxxv)	Press Release Issued by Lafarge S.A. on May 15, 2006.

EX-99.A.1.XXXV

Exhibit (a)(1)(xxxv)

PRESS RELEASE

Euronext: LG, NYSE: LR Paris, May 15, 2006

Lafarge successfully completes cash tender offer for lafarge north america

Lafarge, the world leader in building materials, has today announced that it has successfully completed its cash tender offer for the 46.8% minority stake in Lafarge North America (NYSE & TSX: LAF) that it did not previously own. Lafarge now holds approximately 92.37% of the shares of Lafarge North America (“LNA”).

“We are pleased with the swift and successful completion of our tender offer. This transaction will create value for our shareholders and will immediately be accretive to our earnings per share. We will now work together with our North American teams to deliver the benefits of this transaction. We will streamline our processes, accelerate decision-making and pursue business and growth opportunities even more effectively in the attractive North American market”, said Bruno Lafont, Chief Executive Officer of Lafarge.

The offer and withdrawal rights expired at 12:00 midnight, New York City time, on Friday, May 12, 2006, and Lafarge has accepted for payment all shares tendered. According to the report of the depositary for the tender offer, Lafarge acquired approximately 34,253,627 shares of LNA common stock (including guaranteed deliveries) pursuant to the tender offer. In addition, Lafarge has accepted for payment all exchangeable preference shares of Lafarge Canada tendered pursuant to an offer for exchangeable preference shares that also expired at 12:00 midnight, New York City time, on Friday, May 12, 2006. According to the report of the depositary for the exchangeable preference shares tender offer, Lafarge acquired approximately 444,230 exchangeable preference shares (including guaranteed deliveries) pursuant to the tender offer. Lafarge thus acquired a total of 34,697,857 LNA common shares and Lafarge Canada exchangeable preference shares and holds approximately 92.37% of the LNA common shares and Lafarge Canada exchangeable preference shares taken together as a single class.

Lafarge expects to acquire the remaining shares of LNA not owned by Lafarge or its subsidiaries through a short-form merger. Following the merger, detailed instructions will be mailed outlining the steps that LNA shareholders who did not tender their shares must take in order to obtain payment. After completion of the merger, LNA will be a wholly-owned subsidiary of Lafarge.

LNA will deliver notices to the United States Securities and Exchange Commission requesting the deregistration of LNA shares and to the New York Stock Exchange and the Toronto Stock Exchange requesting the delisting of LNA shares following the completion of the short-form merger.

Exhibit (a)(1)(xxxv)

Note to Editors

Lafarge is the world leader in building materials, with top-ranking positions in all four of its businesses: Cement, Aggregates & Concrete, Roofing and Gypsum. With 80,000 employees in 76 countries, Lafarge posted sales of Euros 16 billion in 2005.

Lafarge has been committed to sustainable development for many years, pursuing a strategy that combines industrial know-how with performance, value creation, respect for employees and local cultures, environmental protection and the conservation of natural resources and energy. Lafarge is the only company in the construction materials sector to be listed in the 2006 ‘100 Global Most Sustainable Corporations in the World’. To make advances in building materials, Lafarge places the customer at the heart of its concerns. It offers the construction industry and the general public innovative solutions bringing greater safety, comfort and quality to their everyday surroundings. Additional information is available on the web site at www.lafarge.com.

Lafarge North America is one of the largest publicly traded construction materials providers in North America. Prior to the tender offer, Lafarge North America was a 53.2%-owned subsidiary of Lafarge.

Contacts

COMMUNICATIONS		INVESTOR RELATIONS
Stéphanie Tessier:	33-1 44-34-92-32	Yvon Brind’Amour:	33-1 44-34-11-26
stephanie.tessier@lafarge.com		yvon.brindamour@lafarge.com
Lucy Wadge :	33-1 44-34-19-47	Danièle Daouphars:	33-1 44-34-11-51
lucy.wadge@lafarge.com		daniele.daouphars@lafarge.com
Louisa Pearce-Smith:	33-1 44-34-18-18	Stéphanie Billet:	33-1 44-34-94-59
louisa.pearce-smith@lafarge.com		stephanie.billet@lafarge.com

Statements made in this press release that are not historical facts, with respect to the completion of the tender offer, the benefits and value creation of the transaction, are forward-looking statements made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. These statements are not guarantees of future performance and involve risks, uncertainties and assumptions (“Factors”), which are difficult to predict. Some of the Factors that could cause actual results to differ materially from those expressed in the forward-looking statements include, but are not limited to: whether the conditions of the tender offer will be satisfied; the cyclical nature of the Company’s business; national and regional economic conditions in the countries in which the Company does business; currency fluctuations; seasonal nature of the Company’s operations; levels of construction spending in major markets and, in particular, in North America; supply/demand structure of the industry; competition from new or existing competitors; unfavorable weather conditions during peak construction periods; changes in and implementation of environmental and other governmental regulations; our ability to successfully identify, complete and efficiently integrate acquisitions; our ability to successfully penetrate new markets; and other Factors disclosed in the Company’s public filings with the French Autorité des Marchés Financiers and the US Securities and Exchange Commission including the Company’s Reference Document and Annual Report on Form 20-F. In general, the Company is subject to the risks and uncertainties of the construction industry and of doing business throughout the world. The forward-looking statements are made as of this date and the Company undertakes no obligation to update them, whether as a result of new information, future events or otherwise.