The 32-year-old had a large collection of extreme Islamist material, including a manual for suicide bombers, the government said.
The dawn raid on Tuesday saw two other Moroccan men arrested.
The unnamed 38 and 33-year-olds both lived with the first man in the residential apartment, according to the Interior Ministry.
The first man had been training them to join ISIS.
Footage of the arrest showed armed police in riot gear storming the apartment building before dawn and men dressed in white robes and motorcycle helmets being grappled to the ground and handcuffed outside the apartment block.
The man had an extremely dangerous profile, similar to that of those who carried out recent attacks in Britain and France, the government said, without giving further details.