In fact, that's what romantic French means. Don't fight when making love. Translated into English, it means making love, not fighting. This slogan is also normal in foreign countries. This is called being more creative. It has nothing to do with obscenity. Is it that making love, a noble activity of human expression of love, has become vulgar?

My msn screen name used to be faissons l'amour, pas la guerre. Even if we're here to have sex and don't fight, I don't think it's obscene.