The City of Love – Solution

The difference hidden in this stunning photo starts with the position of the horse statues. They appear to have been interchanged, with the one on the left positioned to the right and vice versa in the second photo.

In the bottom-left corner of the first photo, we see a couple walking down the pavement, while in the bottom photo, one of them is clearly missing. The third difference has to do with the number of lamp posts in the background, and it’s because the top photo has one less compared to the bottom one.