FIFA's spokeperson told DPA that it's an interanl issue
El Clasico is here this Saturday and Leo Messi could reach Telmo Zarra's La Liga all-time goal record... Many people is talking about a possible tribute to the Argentinian if he manages to reach Zarra's record in El Bernabeu, but a FIFA's spokeperson told DPA that "It's an issue that depends on the Spanish Football Federation and there isn't an specific regulation about it".
So it's not a FIFA case, it depends on the Spanish Football Federation.
La Liga's president Javier Tebas said he was Ok with the tribute if Messi scores a couple of goals, but 5 days ago spoke again and said that if there's any trouble, better not to do it.