Exhibit 99.6

PricewaterhouseCoopers

LLP/s.r.l./s.e.n.c.r.l.

Chartered Accountants

Place de la Cité, Tour Cominar

2640 Laurier Boulevard, Suite 1700

Québec, Quebec

Canada G1V 5C2

Telephone +1 (418) 522 7001

Facsimile +1 (418) 522 5663

CONSENT OF INDEPENDENT AUDITORS

We hereby consent to the use in this amended Annual Report on Form 40-F/A of Æterna Zentaris Inc. for the year ended December 31, 2006 of our auditors’ report dated March 2, 2007, except as to Note 24(g) and (h) which is as of September 17, 2007, on the consolidated balance sheets of Æterna Zentaris Inc. as at December 31, 2006 and 2005 and the consolidated statements of operations, deficit, other capital and cash flows for each of the years in the three-year period ended December 31, 2006.

Chartered Accountants

Quebec, Quebec, Canada

September 17, 2007

PricewaterhouseCoopers refers to the Canadian firm of PricewaterhouseCoopers LLP/s.r.l./s.e.n.c.r.l. and the other member firms of PricewaterhouseCoopers International Limited, each of which is a separate and independent legal entity.