This article studies the theoretical foundations as well as the scope of the privilege of freedom of speech and debates and of the privilege of freedom from arrest granted by the French constitution to members of Parliament. It questions the traditional conception of the French legal writings that both immunities are essential to enable the proper functioning of representative government. If freedom of speech can hardly be surrendered without endangering members’ independence, freedom from arrest, on the contrary, appears nowadays as a rather unnecessary privilege, which Parliament should consider to relinquish.