Weather is amazing in the month of May. With a pair of shades, and a thin layer jacket, you are good to go touring the city by feet. I don't know why people say Parisians are rude to foreigners. To my experience, local residents are very nice at air b&b. I have no problem asking for directions with my broken French. Cute macaroons and beautiful fountains are everywhere!
Eiffel Towel is not so impressive when you looking right next to it. Surprisingly, good pictures come from bird view or long shots.
Notre Dame Cathedral, worth a visit.
Take a nice scenery walk in Palace of Versailles. Plenty shades. and they are all well trimmed, guarding the palace like soldiers. .
At last, don't forget to take some romantic pictures with your amour :)