> I thought France left and rejoined a few decades later, have things changed since then or did they only leave a small part of NATO?

France left the unified military command (in stages) but later returned. To a certain extent the partial breach seems to have been magnified for domestic purposes, as secret agreements on reintegration in the event of an East-West conflict have since come to light. They also have always been outside of the nuclear planning group.

But, in any case, they never left the alliance.