The ambivalence of the French posture within the Atlantic Alliance can be explained by the desire, in Paris, to favour the construction of a European security and defence identity while at the same time playing an important role within the NATO structures. By imposing itself as a new security threat, terrorism has thrown NATO’s traditional tactical scenarios into disarray. This in turn poses a double question, of the redefinition of France’s role in NATO, and of its perception of the fight against terrorism and the role of the EU-NATO tandem in confronting it.