Photo of a square with a billboard

I'm currently processing images I took on a recent trip to Barcelona. I have a panorama shot of a square and in the right side there is an advertising billboard with a photo of a gorilla in it. This billboard takes about 2% of the area of my image. Is that small enough not to matter (don't want to infringe on anybody's copyright), or should I crop away the right part of my image to get rid of this billboard?
--

Alfred Molon
www.molon.de