• really cool eiffel tower.

http://www.shindigz.com/catalog.cfm?caid=1046916&nav=School%20Events%2FProm%2FProm%20Themes%2FParisian%2FPictures%20From%20Paris%20Tower

• balloons. balloons. balloons.
• white carpet for entrance.
  • red rose petals on the carpet.

http://www.michaels.com/art/online/displayProductPage?productNum=wd0007

• cool city cutouts (dont buy them! easy to make..i think..)

http://www.stumpsprom.com/prom/Above-the-City-Lights-Backdrop-Skyline.cfm?caid=775131 or http://andersonsprom.com/p-21157-city-of-lights-and-love-kit.aspx

• lampposts
• bench
• white lights. or candles.