French government prosecutors are currently investigating an oil spill incident believed to have occurred only recently off the east coast of Corsica.
The slick, which experts have estimated to be around 20 nautical miles long, was first sighted late last week by French Navy aircrews that were conducting training exercises in the area.
Following the initial reports of the spill, a patrol vessel of the French customs directorate was despatched to the area to collect water samples.
The French Navy later sent tugs and pollution response vessels to conduct cleanup operations. An official said that an estimated four tonnes of oil have been recovered.
Authorities have also ordered the closure of some of Corsica's beaches and imposed a temporary fishing ban in the nearby waters.
Local media has stated that the slick subsequently broke down into smaller segments that have since drifted farther away from the coast.
Officials have raised concerns that the shifting currents will bring those same oil segments back into the area and cause even greater harm to the marine environment.
No organisation has claimed responsibility for the oil spill. However, Annick Girardin, France's Minister of the Sea, said there are "few doubts" that the spill had resulted from a deliberate discharge by the crew of a passing vessel.
Ms Girardin added that the ongoing investigation seeks to determine who the perpetrators are among 21 suspect vessels that have so far been identified.