While France has been a part of the mutual defense guarantees for something like 60 years, it left the command structure in 1966 because Charles de Gaulle wanted more independence from the US.

Sarkosy has now Sarkozy announced that France’s military will once again be formally integrated into NATO’s command structure.

I’m not sure if this will last, given that the opposition, and no small number of his own party, are rather hostile to the idea.