The Rules of Procedure state that every Deputy must belong to a Parliamentary Group. Within two days of taking their seats, Deputies must tell the Secretary General of the Chamber of Deputies to which Group they belong. The Mixed Group encompasses all Deputies who do not belong to any other Group. Under the conditions laid down in Rule 14, paragraph 5, political units may be formed within the Mixed Group. A minimum of 20 Deputies is required to form a Group.
To form a Group comprising less than twenty Deputies, special authorisation must be sought from the Bureau.
The Groups generally correspond to national political parties or movements represented in the Chamber of Deputies. The Deputies sit in the plenary hall from the left to the centre to the right of the President, depending on their political orientation. The custom of using the terms "left", "centre" and "right" to describe a political position derives from the position of the Deputies in the debating chambers and originates at the time of the French Revolution.