Both are in the France pavillion at EPCOT. Chefs de France is downstairs and the Bistro is upstairs. The food and atmosphere upstairs are more upscale than downstairs. The prices are also higher at the Bistro. We're dined at both and enjoy them both.
We like the Bistro for a quiet evening without our children.
Our children both love Chefs de France. DD loves lobster bisque and they have a really good one at Chefs. DS and I will be headed there next month during our quick trip without DH and DD.