Q: Is it illegal to mark a photo containing a restaurant logo with a CC0 license?

A: Here, you are describing the intersection of copyright and trademark law. While it would be trademark infringement to open your own restaurant called Burger King, or to sell a hamburger wrapped up in a wrapper that says Burger King, you certainly can take a picture of a Burger King restaurant and use it for other purposes. You don't violate any trademark rights by using a picture of a Burger King sign to teach Russian or English. The photographer doesn't either. Also, there is no fair use for trademark infringement, so good thing you're not infringing.

You are right also to be concerned about infringing the photographer's copyright rights. If we assume that the person who posted the photo was the copyright holder, then the Creative Commons license puts the photo in the public domain, so that you can freely use it for whatever purposes you want. Be aware, though, that sometimes the person who posts a photo is not the photographer or copyright holder, and thus doesn't have the right or power to put the photo into the public domain. Anyone who uses such a photo, even though they reasonably believe that the photo is in the public domain, is infringing the rightful owner's copyright rights, and would be liable. A fair use defense to copyright infringement would be appropriate here, but probably not successful.

So, in conclusion, so long as you are satisfied that the image was properly posted by the copyright holder, then you should be fine using it for educational purposes.

A: Ms. Perales answered right on point.

You should consult an attorney to make sure you understand all the implications.

You may be at the intersection of fair use.

Best luck!!!