The Moroccan government said the man was of Moroccan origin and had fought in Syria with al-Nusra before joining the Islamic State group, which has claimed responsibility for the bombings and shootings in the French capital.
It gave the suspect’s initials in Arabic, which can be translated as JA or GA.
He was arrested on Friday in the city of Mohammedia and, according to Morocco, travelled to Syria with one of the Saint Denis suicide bombers.
Abdelhamid Abaaoud, a 28-year-old Belgian thought to have been the ringleader of the November attacks, was killed with other suspects when police raided a house in the Saint Denis suburb of Paris shortly after the shootings.
Morocco provided the tip-off that enabled French police to locate Abaaoud.
It has been holding Abaaoud’s brother Yassine since October, while an arrest warrant has been issued for Salah Abdeslam, who is suspected of taking part in the attacks and is on the run.
The co-ordinated attacks on 13 November targeted central Paris and Saint Denis. Of the 130 people killed, 89 were watching a band at the Bataclan concert hall.
Three suicide bombers also struck near the Stade de France sports stadium in Saint Denis, where the French and German football teams were playing in a friendly. The three bombers and a bystander were killed.
Others were killed when gunmen opened fire at cafes and restaurants in central Paris.