The pedophile had been serving a sentence of 30 years for the rape and filming of youngsters as little as four years old.
Police wielded batons and kept protesters from gathering hear the Moroccan parliament in the center of the capital city of Rabat. Several of the protesters were injured in the process including some journalists.
The pedophile was among 48 Spaniards who were in jail and given pardons by Moroccan King Mohamed VI Tuesday. The pardons were made after King Juan Carlos of Spain requested them, while visiting the country in July.
The demonstration came after a campaign online by activists. Protests also took place in other cities within the country of North Africa.
Protesters were demanding that the King revoke the pardon of the Spaniard, and return him to jail. The government however, said the man had already been sent back to Spain.
The Foreign Ministry of Spain confirmed over the weekend that the man had returned to Spain and that he was named Daniel Galvan Vina.
According to the list of pardons, the man was born in Iraq but nationalized in Spain.
A lawyer for the victim’s families said Galvan was convicted just 18 months ago of filming and raping children between the ages of 4 and 15.
No immediate comment was made by the royal palace, but the Ministry of Justice said the pardon was issued using the national interests of Morocco due to the friendly relationship between the two countries.
The king, pardons prisoners, like many other rulers in the Middle East on special days, but his decision to pardon the many Spaniards at the request of King Juan Carlos, has upset many Moroccans.