is there any difference between filet, french and pole beans?

Pole beans are long vining beans. They can be flat podded types or more slender round-podded varieties that can be picked young to use as French or filet beans -- 'haricot verts.' There are varieties that are particularly well-suited to being used as 'haricot verts' but most of them seem to be bush types. 'Fortex' is a pole bean variety that is well suited to being picked young for 'haricot verts' or filet beans. (Me, I like large, tender flat-podded pole bean varieties myself and only eat 'haricot verts' *very* occasionally at ambitious restaurants.)

"French beans" might also refer to varieties that are used for green shell beans (usually with the word 'horticultural' plumped into the middle). These are also sometimes called 'flageolet' beans. The immature beans are what you are after. Some of these varieties are dual purpose in that you can harvest young beans to cook as snap beans or wait until the beans inside size up (but are nowhere near dry) and shell them out to cook as fresh beans.

And "French" in relation to beans is also used for normal full-sized round podded beans that have been run through a slicer to cut them into strips that maybe vaguely resemble authentic 'haricot verts.'