The French definitely helped Israel construct a secret nuclear reactor and plutonium processing plant at Dimona. They may have given other assistance as well. As one member of the French nuclear program, Bertrand Goldschmidt, crudely put it, "not only did we take the girl when she was a virgin, but we made her pregnant." Of course, Israel had to do quite a lot of the work — they were not simply handed warheads — but the French gave important, material assistance that was done in the interest of proliferating.

Anyway, this is all very well documented. The French motivation for doing this was partially about guilt from the Holocaust, and also out of a desire to complicate matters for the Arab nations, in order that they would spend more time worrying about Israel and less time worrying about France's colonial holdings in Algeria. See, e.g. Kroenig, Exporting the Bomb, among other sources on the Israel program in particular (e.g. the work of Avner Cohen).