The French. The Caro-Kann just seems to be losing for black in every variation. Advance Variations and the bishop gets trapped at worst, traded at best, but often seems to just become a non-factor like the queenside knight. Breyer Variation in the style of the Reti Tennison Ballistic Missile Countergambit is very strong, and if they don't take the original gambit white's structure and activity are both still stronger. Advanced Panov seems like a better Scandinavian. Fantasy Variation is literally a fantasy. Exchange Variation is one of the best variations for black but it's still better for white. I think there's a reason that c6 is extremely rare outside of the Caro-Kann. Blocking knights, trading bishops for knights with no provocation, and wasting tempos in the early game go against the every opening principle in the book aside from "don't bring the queen out early", as your center control in the Caro-Kann usually isn't even that good as compensation.
Compare all this to the French, in which positions tend to be quite similar except the knight isn't blocked, the LSB is safer, and you haven't wasted a tempo with c6 and can play c5 directly, allowing for better queenside counterplay and center control.
The French has a very undeserved reputation for being dubious, especially at the amateur level.
Amateurs very rarely play the critical variations; 3. e5 and even 3. exd5 are most commonly played, both of which offer no serious advantage (or none at all in the case of the exchange), and even when they do black has good chances to launch a counterattack of his own (using the open c-file, ... a6/... b5/... b4 (undermining white's center) or a timely ... f6 and using the open f-file). Black also has dangerous variations that the white side is often unaware of, like the Burn variation with ... gxf6; look at Petrosian's games, for example the one against Fischer in their 1971 match. (In that game Fischer avoided the most critical line with g3, because he knew the danger.)
Amateurs also like to say the light squared bishop is bad. On the other hand, in the QGD black had the same 'bad' bishop and no-one disagrees the QGD is a top tier defense. Good French players will also make that bishop work.
It's also remarkable how players often claim the Caro-Kann should be the preferred defense of the two and the French is still more played at EVERY level. Apparantly it's just a fine opening on the non-super GM level.