The councillors are suspected of having used the trip to become illegal immigrants.
Moroccan television said the councillors, from the north-eastern town of Berkane, failed to return from a trip to the French town of Bondy, in the suburbs of Paris, which has a twinning arrangement with Berkane.
The report, broadcast on Wednesday, said that none of the 12 councillors had been heard from since they left on their trip eight months ago.
In the meantime, the temporary visas with which they entered the country would have expired.
The Berkane town council chairman, Mimoun Chettou, was quoted as saying that he did not believe the 12 had simply used the trip to begin new lives outside Morocco.
"They aren't illegal immigrants, they have their reasons," he told the public television channel 2M.
"I've heard say that one of them had said he was staying in France to get medical treatment."
However a local resident of Berkane did not believe that version. "It is a dishonour for our country," he said.
Each year thousands of people from Morocco and other African countries try to cross the Mediterranean and gain access to the wealthier countries of the European Union.
But many die en route, or are caught by coastguards and border police as they try to cross in small boats – often leaving from Morocco and heading for Spain.
Pending new local elections in Morocco on 12 September, the town council in Berkane would be missing a full third of its members.