One of France's most modern fighters was sent to check on the single-seated tourist plane over the remote Ardeche region Saturday after it flew through restricted airspace near a nuclear plant and was judged to be manoeuvring suspiciously.

As the Rafale drew near, the air force pilot "witnessed very erratic behaviour in the cockpit (of the tourist plane), real agitation", a military spokesman told AFP.

"Over the course of a few minutes, he saw the door open and packages being thrown out."

The suspected trafficker, a Polish national with a past drugs offence, was arrested after he landed at an airstrip in Lanas in the Ardeche region, the local prosecutor's office said in a statement on Tuesday.

Investigators found around 15 packages on the ground, containing an estimated 30 kilograms (66 pounds) of a white powder that is being analysed.

They also found more than 45,000 euros ($49,000) in the cockpit of the Polish-registered plane, as well as in the pilot's bag.

The incident follows the discovery of more than two tonnes of cocaine on beaches of northern France in March.

Last year, French authorities seized a record 156.7 tonnes of drugs, according to the interior ministry.