Exhibit 1

JOINT FILING AGREEMENT

In accordance with Rule 13d-1(f) of the Securities Exchange Act of 1934, as amended, the undersigned hereby agree to the joint filing on behalf of each of us of an amendment to Schedule 13D relating to the Ordinary Shares of Celanese AG, a German stock corporation, and that any subsequent amendments thereto filed by any of us will be filed on behalf of each of us. This Agreement may be included as an exhibit to such joint filing.

DATE:	March 12, 2004
BCP CRYSTAL ACQUISITION GMBH & CO. KG
By:	/s/ Chinh Chu
	Name:	Chinh Chu
	Title:	Authorized Person
BCP ACQUISITION GMBH & CO. KG
By:	/s/ Chinh Chu
	Name:	Chinh Chu
	Title:	Authorized Person
BCP HOLDINGS GMBH
By:	/s/ Chinh Chu
	Name:	Chinh Chu
	Title:	Authorized Person
BCP MANAGEMENT GMBH
By:	/s/ Chinh Chu
	Name:	Chinh Chu
	Title:	Authorized Person
BCP LUXEMBOURG HOLDINGS S.À R.L.
By:	/s/ Chinh Chu
	Name:	Chinh Chu
	Title:	Authorized Person

BLACKSTONE CAPITAL PARTNERS (CAYMAN) IV L.P.
By:	Blackstone Management Associates (Cayman) IV L.P., its general partner
	By:	Blackstone LR Associates (Cayman) IV Ltd., its general partner
		By:	/s/ Chinh Chu
			Name:	Chinh Chu
			Title:	Authorized Person
BLACKSTONE CAPITAL PARTNERS (CAYMAN) IV-A L.P.
By:	Blackstone Management Associates (Cayman) IV L.P., its general partner
	By:	Blackstone LR Associates (Cayman) IV Ltd., its general partner
		By:	/s/ Chinh Chu
			Name:	Chinh Chu
			Title:	Authorized Person
BLACKSTONE FAMILY INVESTMENT PARTNERSHIP (CAYMAN) IV-A L.P.
By:	Blackstone Management Associates (Cayman) IV L.P., its general partner
	By:	Blackstone LR Associates (Cayman) IV Ltd., its general partner
		By:	/s/ Chinh Chu
			Name:	Chinh Chu
			Title:	Authorized Person

BLACKSTONE MANAGEMENT ASSOCIATES (CAYMAN) IV L.P.
By:	Blackstone LR Associates (Cayman) IV Ltd., its general partner
	By:	/s/ Chinh Chu
		Name:	Chinh Chu
		Title:	Authorized Person
BLACKSTONE LR ASSOCIATES (CAYMAN) IV LTD.
By:	/s/ Chinh Chu
	Name:	Chinh Chu
	Title:	Authorized Person
/s/ Peter G. Peterson
PETER G. PETERSON
/s/ Stephen A. Schwarzman
STEPHEN A. SCHWARZMAN

BLACKSTONE CRYSTAL HOLDINGS CAPITAL PARTNERS (CAYMAN) IV LTD.
By:	/s/ Chinh Chu
	Name:	Chinh Chu
	Title:	Authorized Person
BLACKSTONE CAPITAL PARTNERS (CAYMAN) LTD. 1
By:	/s/ Chinh Chu
	Name:	Chinh Chu
	Title:	Authorized Person
BLACKSTONE CAPITAL PARTNERS (CAYMAN) LTD. 2
By:	/s/ Chinh Chu
	Name:	Chinh Chu
	Title:	Authorized Person
BCP CRYSTAL HOLDINGS LTD. 2
By:	/s/ Chinh Chu
	Name:	Chinh Chu
	Title:	Authorized Person