An explosion on Sunday outside a business school in the western city of Nantes run by one of France's first Muslim departmental governors caused minor damage but no injuries, officials said.
Last week, the car belonging to Aissa Dermouche - the Algerian-born director of the Audencia school of management and the new top administrator for the eastern French department of Jura - was destroyed by an explosive device.
Windows were broken and the door damaged at the Audencia school in Nantes, which the 57-year-old Dermouche has run since 1989, officials said.
The prefect of the Loire-Atlantique department, Bernard Boucault, immediately went to the scene and an investigation has been opened. Police were at the scene taking samples for scientific analysis.
The president of the Audencia school, Jean-Francois Moulin, declined to comment on the incident.
The explosive device used in Sunday's blast, which was placed near a guard post, was "not very sophisticated," according to a source close to the probe.
Dermouche, who came to France at the age of 18, is the first departmental governor, or prefect, from the generation that immigrated from North Africa in the 1960s. The handful of previous Muslim prefects started their civil service careers before 1962 when Algeria was officially part of France.
His nomination 10 days ago came at a time of growing concern over how to better integrate the five million-strong Muslim community in France, and moves by the government to ban Islamic headscarves and other religious insignia in schools, a step many Muslims see as an assault on their basic freedoms.