Guillaume Canet is just an amateur, but unlike Charlotte, a sensible amateur, who rides for passion and fun, and is perfectly conscious of what's his level.
He doesnt' pretend to be something that he is not, even if he also qualifies himself as a "perfectionist".
And it rings true. In the Jappeloup film he jumped 1.50 jumps but he is conscious that this wasn't just a film and competition is different, so he is humble enough to ride 1'05-1'15m. competitions for now, because that's the level he knows he can do things properly.
He also has a horse who's adapted to his level. He rides a 1'20/1'25 horse, which is more than enough is you are jumping 1'10.
If he keeps on riding regularly (he says his profession is acting, and he only rides when he has the time), he'll probably get better results than Charlotte.
You can watch him here:
Epreuve Partenaires N°1 - Guillaume Canet - Vidéo Dailymotion
You can listen to him explaining himself here, but of course it's in french:
Guillaume Canet en selle à Bordeaux / France Bleu
In France you can have several type of riding licences, that give you the right to enter diferent types of competition. Those who have AM under their name have amateur licences, and those who have PRO have a professional one.
Edit: You can see Charlotte in this video from the 1st day of competion. You have to click where it says "Les people en compétition". Guillaume Canet and Philippe Monet talk to the cameras. Charlotte probably thinks she is above it and has Rozier talking. You can see her getting eliminated, thought, and Rozier making excuses for her.
Les "peoples" en compétition - France 3 Aquitaine
I'll attempt a quick translation, please excuse my clumsy english:
"It is very difficult for a young girl like this to ride, and to manage to relax, to enter correcty, but she has such passion... She has the will. Also, she is a little bit tired she has a small flu".
I mean. What does he mean by a young girl "like this"? And what in earth is a "small flu". You either have the flu or you don't. Otherwise you just have a cold!
But it's specially telling the way he says ..but she has the passion, and the will... " At least he is the only one decent enought not to mention her "talent".
Edit 2: she's been eliminated again:
The Result of Prix des Partenaires at Jumping International de Bordeaux
Probably she was still tired, from her "small flu"