The Eiffel Tower by night is a true beauty. I can definitely see how 10,000 tons of metal can be a symbol of romance.
On the right and below is the Sacré-Cœur basilica in Montmartre, which also happens to be the highest point in Paris.
Go see it. Warning: there are quite a few stairs to climb to get there. Had to take a few breathers. The APC outlet is nearby. Black Market coffee shop is nearby. And the Hey! Modern Art and Pop Culture exhibition at Halle Saint Pierre is nearby as well, which is an absolute must.