French authorities have said that imam Hassan Iquioussen has disappeared and most likely fled to Belgium after France's top administrative court on Tuesday gave the green light for his expulsion to Morocco.
The imam was accused by the court of hate speech.
The case landed before the highest court after Paris judges blocked the imam's deportation, which the interior ministry ordered in late July.
Iquioussen, 58, reaches tens of thousands of subscribers via YouTube and Facebook accounts from his home in northern France.
He was born in France but holds Moroccan citizenship.