Sicard was a real beast in his last espoir year, and was already very strong the year before, which was his first season in Spain. His marvellous espoir year culminated in a Tour de l'Avenir win overall, and an U23 World Champion title. He also won a race among the pros while still being riding for Euskaltel reserve team. Not bad, eh ?
So, some people at the French federation started investigating how on Earth it was possible that local federation members and local teams or clubs officials had been blind to such an amazing talent.
Turned out he was decently talented, twice National champion on track in age categories (Madison + scratch, arguably not the most significant events), third in his regional championship, etc. Nothing worth of a world beater.
Then he changed teams. And countries. He joined Orbea (Euskaltel junior team). And started improving, a lot, in just two seasons.
What had he done there ? You've figured it out. And he was/is a super responder to some products.
Eventually he turned pro, which is logical for such a super talent. But there are plenty of controls there, and the bio-passport. It's still possible to dope, I don't know if he does, but it's much more complicated than at the lower level. So, Sicard is hardly an average pro nowadays, and there's not much more to expect from him, unless he'd get access to a new wonder drug.

@ Ian -