Are green lentils the same thing as French lentils?

I agree with the other answers and would add that in looking for French lentils, look for "du Puy" (or le Puy or de Puy) lentils.

Green lentils are a little larger and lighter in color than French lentils. The latter cook up firmer, maintaining their shape, and are suitable for salads. Green lentils soften up more as they cook, making them more suitable for soups.

Yes - French lentils are also called French green lentils