Everything is not signed and sealed yet. But it appears that the constructive leadership of France has softened European resistance to joining the United States and a few far-flung smaller nations in providing a Sinai peacekeeping force. Israel's scheduled withdrawal from Egyptian territories there is dependent on such a force, and the politics of the United Nations ruled out a UN assemblage. Now, after President Mitterrand's breaking of the ice, Britain and Italy are reported likely to cooperate. Vive la France!