Malika, if you explore (or have already) sensory issues and sensory diet, it might seem a bit too much at first. As I was reading some books, taking V to Occupational Therapist (OT) at first, I was thinking to myself: how in the world am I suppose to integrate a sensory diet in our life?? It seems like a LOT of work and also kind of fake (ie: V walk like a crab to get your clothes, yeah right...).
And slowly I digested all the information I read, took people's adivice on this board (basically telling me not to give up and "believe") and I am now able to know where V comes from in his supposedly "bad" behavior. Little example: V would repeatedly step on my father's toes. And it was no accident. My father would get annoyed and was real close to yell at him to now stop it. I explained that it was indeed intentional but not malicious in any way. V is sensory seeking (most of the time, but not always), he loves my father and wants to feel him. A simple touch is not enough for him, he needs lots of pressure to feel his body and what's around him (ie: weighted blankets, bear hugs, lots of crashing, breaks toys, etc...). We explained to V that stepping on toes was painful to other people and my dad would squeeze V in his arms instead. Problem solved.
I've also learned that V does the sensory seeking on his own, he does not need me to help him on that much. But he needs me to help him calm down. He just cannot do it on his own. So at home, we have a lot of soothing techniques and gears available to him for this purpose.
Without my help to calm down, V can look like a hyper child. If not stop in his track, he will eventually become dangerous to himself and others.
His Auditory Processing Disorders (APD) can also make him look like ADHD: he fidgets, looks around, an't sit still, can't answer questions... But the root of the problem: his brain can't make sense of the words and questions, he becomes bored and therefor distracted. His Speech Language Pathologist (SLP), makes him work on an activity 5 minutes and then relax 2 minutes. Is it an attention problem or hyper activity problem? No. It is just so much work and concentration to make sense of what is being said that V becomes tired.
I could not direct you to the right place, but after searching some French websites on Autism Spectrum Disorders (ASD), I know that sensory issues are known in France. Maybe mostly in Autism Spectrum Disorders (ASD) circles? I don't know. But you might want to check Autism Spectrum Disorders (ASD) and sensory processing disorder (SPD) together first. You might then find some info on sensory processing disorder (SPD) knowledgeable professional.
Good luck!