This article describes the process of parliamentary control of EU legislative proposals regarding their conformity with the principle of subsidiarity (so called "early warning system") in the Chamber of Deputies. It also provides thorough analysis of the opinions of the Committee on European Affairs of the Chamber of Deputies, in which EU Affairs Committee found EU legislative proposals incompatible with above mentioned principle.
The paper also discusses some criteria for reasoned opinions from national parliament; it focuses mainly on extensive/restrictive notion of reasoned opinions.