If AA and AF are your only options, I agree with the previous posters: go AA. (I speak good French. It doesn't matter.)

However: have you considered DL from STL to either CVG or ATL, then CDG and almost anything from there? You'd have to leave a bit earlier in the day, but their Business Elite is superior (IMHO, and all things being equal I generally prefer AA to DL) to AA's business class. DL has dropped first, which AA has not, so their Biz Elite is a bit of a hybrid.

AND: if you have (or can get) AmEx Platinum, register for their promo by May 1, and fly DL Business Elite any time April through June, and pay for it with that card, you get a bonus of 80,000 (yes, you read that right, EIGHTY THOUSAND) miles. That's over and above the flight miles, the status bonus, and 1 mi/$ in Membership Rewards, so you should net close to 100K. Just call 877-BIZELITE with promo code 2005. For 80 thou miles, to say nothing of a better seat across the pond, I'd leave St. Louis two hours early and put up with a bit of extra travel on the far end.