The heads of the two animals were found attached to two pillars at the entrance to the Salam Mosque in Montauban, near Toulouse.
Pigs are considered unclean by Muslims, who are forbidden from eating them.
Muslim leaders have condemned the act, while the mayor of Montauban branded the incident an ‘odious and blasphemous act toward the Muslim community’.
Police have launched an investigation. Muslim leaders said the vandalism was especially shocking because it happened during the holy month of Ramadan.
Abdallah Zekri, a regional Muslim leader based in Nimes, said, “This was meant to dirty this place of prayer.” It was the first such incident in Montauban, a town with a population of around 56,000 near the city of Toulouse in southern France.
In 2009, pigs’ trotters were hung on a mosque in Castres, also in southern France, and a Nazi swastika was painted on its walls along with racist and nationalist slogans.
The discovery of the pigs’ heads came a day after officials in the northern Paris suburb of Gennevilliers reinstated four summer camp counsellors who had been suspended for Ramadan fasting.
After an outcry, the town decided that during the month of August it would not apply a clause in the labour contract requiring summer camp counsellors to be fully fed and hydrated, a statement said.