Former Site of Masonic Temple
The Geocache is found as a French Foot Gunner Helmet by burning the garbage in the can. Now burning the wads of papers in the steps, the left crate and the newspaper will get you the soccer ball, hard hat and the letter O. Finally, the triangle piece is found by using the socket wrench on the manhole.
At Notre Dame, the French Jeweled Crown is your Geocache item; its the base of the candlestick. Break the bowl on the table to get the French Coin and place 6 red gems in the diamond holes at the bottom of the stained glass window to take the skull from the ark.
Now head on over to the Pantheon where the Geocache item is a French Bone China Teacup and Saucer (its at the upper left dome) Dust the left column, burn the lower right picture, and break the vases to get the trident, music notes, and paintbrushes respectively. For the triangle piece, you need to place the mirrors in each statue's hand and in the niche left of the armor.
After the Pantheon, the National Library is your next stop. The Geocache item is a handcrafted mantle clock this time, which is very easy to spot. The map book is found if you type on the keyboard "D-12-5". Now get to bookcase D, top shelf and the 5th book from the left. Get the book and place it on the stand, before you use the scissors to cut the map out.
Lost Napoleonic Treasure
The second to the last area is at the Grand Palace. The Geocache item is a bust of Napoleon. Break the lower left crate to get the rope. Dust the balcony to get the stapler too, and finally use the impact wrench on the bolt to get the triangle piece.
Finally, make your way to the Parisian Catacombs where the geocache item is the Knight's Templar Coin by breaking the pot. Now break the vases to get the necklace, X Bone and P bone. Then dust the wall to get the cross. Finally, place the prism on the center platform and the lanterns on the left and right platforms. Light the lanterns and the place the bones on the lights to get to the treasure