France says Iran 'illegally' holding French national since May
The foreign ministry said the French national was under consular protection, its embassy in Tehran was in regular contact with him and that it was "attentively following the situation of our fellow national".
French news publication Le Point said the 35-year old, whom it named only as Benjamin, was arrested in northeastern Iran near the Turkmenistan border where he was travelling as a tourist in a van, according to his Iranian lawyer who also said that lawyers had not been granted access to case files.
Quoting a source close to Benjamin, Le Point said he had spoken by telephone to his family, but his detention was illegal because "the authorities never produced the slightest case file or any explanation for his detention".
Iran has in recent years repeatedly detained foreigners and dual nationals on charges campaigners and governments say are unfounded, with the prisoners only going free after months and sometimes even years of painstaking negotiation.
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High-profile releases of foreign prisoners in Iran - of American Xiyue Wang in December 2019, American Michael White in March 2020 and Frenchman Roland Marchal, also in March - were all accompanied by the release of Iranians held abroad on sanctions-busting charges.
But concern over the tactics intensified last autumn with the release of Australian-British lecturer Kylie Moore-Gilbert, who was freed in an apparent exchange for three Iranians convicted in Thailand over a 2012 bomb plot that Israel linked to attacks against its interests.
Agencies contributed to this report.