Hello,
I just want to ask if I do understand this right.
My son is in middle school and few days ago I had found out that he is sitting in his class without a desk, using second chair as a desk. That desk was removed from him as a punishment by the teacher, who dislikes his poor behavior in the class.
All this stuff was delivered in such a manner, that everybody in the class started to
jeer at him together with teacher, who asks him all the time if he likes to sit on 2 chairs.

The question is is that OK to do that from the side of teacher and where can I apply for help and protection?

Did you try talking to the Principal? If not then I would make that my first step. Open the discussion and see if you can work with the school to find a resolution.

Absolutely the teacher is overstepping their boundaries. Bullying is not permitted at school...I believe there is zero tolerance, even by a teacher.  Stop it immediately. Tell the teacher, tell the principal and tell the Board of Ed. The teacher needs that added to their file so they can be retrained.

Teachers need to know that children are an extension of their parents.  Would a teacher talk to a parent like that? I dont think so.

Hug your child and tell them not to tolerate abuse from anyone, including adults and teachers. That next time, your child can request to call you immediately for your support input etc.

Well first of all you must address the mis-behavior of your child, this teacher, as silly as it is is trying to do their job, and when they don't have the classes attention how can they?  Do not make light of disrespect and don't take the childs side first.  You should confront the child about the bad behavior, get that worked out with your own at home disciplne and then together make the child appologise to the teacher and try and work as a unit to stop the bad behavior and the bad discipline.  When the child isn't accountable for his/her bad actions they shouldn't expect to get comfort when they aren't pulling their own weight. Teach children wisely and teach them humility and to be first respectable to those whom YOU have given authority over them for the day or when ever.  Remeber you wouldn't tolerate bad behavior at home.

Yes, definetley! No matter how difficult it is for the teacher, it is not professional and appropriate to encourage the class to jeer at misbehaving children.

Go to the principal--not that itslikely to do anything--and ask other parents whose children are in the classroom if their kids have had any problems with this teacher.