Eleven French nationals detained in Thailand for drug trafficking

"The situation of our fellow citizens is being closely monitored by the relevant departments of the foreign ministry in Paris, which are in contact with their families," a diplomatic source told AFP.

According to accounts from relatives of some of the young people interviewed by French daily Liberation, they might have been duped by traffickers to act as drug mules in exchange for free vacations.

The holiday offer allegedly came from the manager of a smartphone trading company and, according to their relatives, the French nationals were unaware of the suitcases' actual contents, Liberation said.

The daily identified at least five young people aged 18 to 26 who were arrested at airports in Thailand and Hong Kong.

AFP spoke to a woman whose 20-year-old brother-in-law was arrested in mid-July as he was preparing to travel from Thailand to Paris with another Frenchman.

In their locked suitcase, for which they did not have the combination, customs officers discovered "16.8 kilogrammes of cannabis".

"They were shocked. They really weren't expecting it," the woman said.

She said he was contacted through Snapchat by someone who claimed the courier run was "100 percent legal" and that it involved transporting phones.

"Everything was covered: flights, accommodation on site," she said. "So he took it seriously."

"He was the victim of a 'Thailand plan.' He was snared," she added.

The French prosecutor's office tasked with combatting drug crime said investigations were under way.

"Our objective is to identify the organisers and potential networks involved, and to understand how these operations work: how these young people are recruited, looked after, whether other individuals are involved, and so on," PNACO said.