[DMGRS]

Hopefully my feedback will help members sending items to France.

Good:
DPD (cheap, usually under a week)
DHL (expensive but very quick)
UPS (expensive but very quick)
FedEx (very expensive, but overnight in most cases)
ParcelForce / GLS (well priced and relatively quick, 3-5 days)
TNT (expensive but very quick)
Basically all of the large name couriers seem to be pretty good for Europe in general.

Bad:
UK Mail (took 3 weeks last time!)
Royal Mail (unpredictable - anywhere between a week and 6 weeks)
MyHermes (excellent with the UK at the moment, but deliveries to France were taking 3 weeks plus)
Landmark Global (uses Hermes and a local French courier, up to 4 weeks)

Just my 2p and my experience. We'll always try and use a customer's requested courier for International deliveries, although for cost reasons this isn't always practical.