A new Spanish law that took effect Jan. 2 bans smoking tobacco in all enclosed public places.
An official with the Health Department of Barcelona's city government said the warning stems from a complaint filed by someone who saw the play.
The play's director, Roger Pena, is quoted in the Spanish newspaper El Mundo as saying the actors smoke herbs like basil, not tobacco, and called the complaint far-fetched and ridiculous.
"At this rate we will end up banning movies in which people smoke and take cigarettes away from Humphrey Bogart," the paper quoted him as saying. "It is not our desire to defend smoking."
The official said town hall is waiting to hear back from the theater before deciding to whether to proceed with the complaint, which could ultimately lead to a euro10,000 ($13,500) fine if it is found the actors are in fact smoking tobacco.
This official spoke on condition of anonymity in line with department rules.
The Spanish Health Department said that if the actors are in fact smoking herbs, no law is being violated because the new legislation refers only to tobacco.