EXHIBIT 99.2

JOINT FILING AGREEMENT

The undersigned acknowledge and agree that the foregoing statement on Schedule 13D is filed on behalf of each of the undersigned and that all subsequent amendments to this foregoing shall be filed on behalf of each of the undersigned without the necessity of filing additional joint filing agreements.  The undersigned acknowledge that each shall be responsible for the timely filing of such amendments, and for the completeness and accuracy of the information concerning it contained therein, but shall not be responsible for the completeness and accuracy of the information concerning the others, except to the extent that it knows or has reason to believe that such information is inaccurate.

This Agreement may be executed in counterparts and each of such counterparts taken together shall constitute one and the same instrument.

Dates as of:  December 2, 2013.

	CAISSE DES DÉPÔTS ET CONSIGNATIONS
By:	/s/ Alain MINCZELES
	Name:	Alain MINCZELES
	Title:	Head of Finance Division
	BPIRANCE PARTICIPATIONS S.A.
By:	/s/ Nicolas DUFOURCQ
	Name:	Nicolas DUFOURCQ
	Title:	Chairman of the Board and Chief Executive
	Officer
	BPI —GROUPE (BPIFRANCE)
By:	/s/ Nicolas DUFOURCQ
	Name:	Nicolas DUFOURCQ
	Title:	Chief Executive Officer
	EPIC BPI-GROUPE
By:	/s/ Arnaud CAUDOUX
	Name:	Arnaud CAUDOUX
	Title:	Chief Financial Officer
	BPIRANCE INVESTISSEMENT
By:	/s/ Nicolas DUFOURCQ
	Name:	Nicolas DUFOURCQ
	Title:	Chairman of the Board

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	FONDS DE CO-INVESTISSEMENT DIRECT
By:	/s/ Nicolas DUFOURCQ
	Name:	Nicolas DUFOURCQ
	Title:	Chairman of the Board of Bpifrance Investissement, manager of Fonds de Co- Investissement Direct
	NICOLAS DUROURCQ
By:	/s/ Nicolas DUFOURCQ
	Name:	Nicolas DUFOURCQ

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