FORM 6 - K



                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549


                        Report of Foreign Private Issuer
                    Pursuant to Rule 13a - 16 or 15d - 16 of
                       the Securities Exchange Act of 1934


                             As of December 1, 2006



                                  TENARIS, S.A.
                 (Translation of Registrant's name into English)


                                  TENARIS, S.A.
                           46a, Avenue John F. Kennedy
                                L-1855 Luxembourg
                    (Address of principal executive offices)


     Indicate by check mark whether the registrant files or will file annual
reports under cover Form 20-F or 40-F.

                         Form 20-F   x       Form 40-F
                                   -----               -----

     Indicate by check mark whether the registrant by furnishing the information
contained in this Form is also thereby furnishing the information to the
Commission pursuant to Rule 12G3-2(b) under the Securities Exchange Act of 1934.

                             Yes                 No      x
                                   -----               -----

     If "Yes" is marked, indicate below the file number assigned to the
registrant in connection with Rule 12g3-2(b): 82- . -




The attached material is being furnished to the Securities and Exchange
Commission pursuant to Rule 13a-16 and Form 6-K under the Securities Exchange
Act of 1934, as amended. This report contains Tenaris's press release announcing
its has completed the sale of Dalmine Energie participation to E.ON.


   Tenaris Completes Sale of Dalmine Energie Participation to E.ON

    LUXEMBOURG--(BUSINESS WIRE)--Dec. 1, 2006--Tenaris S.A. (NYSE:TS)
(BCBA:TS) (BMV:TS) (BI:TEN) announced today that it has completed the
sale of a 75% participation in Dalmine Energie, its Italian energy
supply business, to E.ON Sales and Trading GmbH (EST), a wholly-owned
subsidiary of E.ON Energie A.G. and an indirect subsidiary of E.ON
A.G. EST paid a total of EUR 46.5 million (approximately US$61
million) for the participation, implying a total enterprise value for
Dalmine Energie of EUR 79.5 million (approximately US$104 million).

    Dalmine Energie began operations in 2000 following the partial
deregulation of the Italian energy sector and initially supplied
energy to Tenaris's Dalmine seamless pipe mill and to other users in
Northern Italy. Since then, it has grown rapidly and has become one of
Italy's largest independent energy wholesalers. In 2005, the
enterprise sold 3 TWh of electricity and about 1,000 million cubic
meters of gas to about 1,100 industrial and business customers
including Tenaris.

    Tenaris is the world's leading manufacturer of tubular products
and services for the oil and gas industry and a leading supplier of
tubular products and services used in process and power plants and in
specialized industrial and automotive applications.

    CONTACT: Tenaris
             Nigel Worsnop, 1-888-300-5432
             www.tenaris.com



                                    SIGNATURE


Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this report to be signed on its behalf by the
undersigned, thereunto duly authorized.



Date: December 1, 2006



                                  Tenaris, S.A.




By: /s/ Cecilia Bilesio
- -----------------------
Cecilia Bilesio
Corporate Secretary