I don't see how the police can do anything. It's three French dudes opinion vs one foreign person's opinion.
I don't see how the camera can be admissible as evidence either. The man still has it, since he put pictures from it onto his blog thing. Which means there's a question of whether or not the images have been tampered with, or if what they show is actually what it is said is going on at the time. The judge would say "non" and then it's back to 3 Frenchmen vs 1 foreigner.
There's a thing about this whole thing. Stuff like CCTV cameras, and so on, falls under Data Protection laws and so on, but people with cybernetic eyes aren't covered.
Privacy stuff too. Or even confidentiality stuff. You cannot allow a person with a cybernetic eye into a courtroom, and have them taking pictures willy nilly, of people that are accused, but not convicted, and all sorts of other stuff like that.
Cybernetic eyes, the storage of stuff, has ramifications for crime and justice and so on. Something happens, and there's an appeal for witnesses, and Johnny Cyberman turns up, claiming to have seen it. And he's modified the images on his cybereye to frame Ethnica Z. Foreigner for the crime. Even if it's no good for a court of law, Johnny can talk to the press, or blog about it or whatever, putting up the pics. This would screw all sorts of stuff up.