This simple move is one of my favorite lines against the Petroff. White's play isn't very difficult and although he doesn't have an objective advantage, I can say that nothing gives him an advantage against this solid defense anywway.
1. e2e4  1... e7e5  2. g1f3  2... g8f6  3. f3e5  3... d7d6  4. e5f3  4... f6e4 