This is an interesting practice. Britain has the PM and ministers lined up facing their opposition "shadow" counterparts across the floor of the House, and sometimes the debate can be fierce. In France, the PM is only really called to account when making her/is opening policy speech (which François Fillon did this week), or if there's a censure motion (no-confidence). In neither case (UK or France) is there an obligation to respond to criticism and questions as in the procedure you describe, metavision. Thanks for telling us about it!