Hi everyone. My question concerns the right to use fonts.

I haven't found any posts on the forum that answer this question.

 

I design fonts that I sell on marketplaces. Most of these marketplaces don't give any information about the buyers, so I can't know the identity of my customers.
Recently I've seen that 2 publishers are using one of my fonts for their covers.
I assume they bought the license for the font, but how would I know ?

How can I know if they have the right to use the font ?

Well, you would have to ask them directly. Legally, it’s their responsibility to be able to prove that their usage is licensed. 

Thanks @Ralf Herrmann for your so quick answer!

I thought about that, but who can I contact? These publishers are big companies, and I have no contact. More, this is a very specific question that most of the salaries of these companies don't know anything about…

BTW I'd like to take this opportunity to congratulate you on your very informative and well-constructed videos.
And I love your accent!

Your resellers should be able to verify via their sales records that a particular publisher has purchased a license for a specific font, and should be able to tell you that much. Many larger resellers have staff dedicated to monitoring unlicensed usage (smaller resellers may not).

If your resellers balk at sharing that information, I’d contact the publishers' legal departments directly. State that you noticed your typeface being used on the cover of one of their books (give them the title, publication date, and even share an image), and ask them—politely—to please provide proof of their purchase of a commercial font license. Fear of litigation will likely prompt a quick response.

I’ve done a fair amount of work for regulated industries (banking, pharma), and my most recent pharma client started requiring type audits—in addition to still image/video/music/talent agreement audits—just last year. Before any job is approved for distribution (digital or print), all applicable licenses have to be accounted for and pass a review by asset librarians. Most large advertising agencies have similar safeguards in place.