A Russian court on Monday upheld a three-year prison sentence for French researcher Laurent Vinatier, one of several Westerners jailed by Russia during the Ukraine offensive.
France condemned the sentence as "arbitrary" and demanded Vinatier's "immediate release", after accusing Russia of taking Westerners hostage.
Vinatier, who works for a Swiss conflict mediation NGO, was arrested last summer as tensions with France and other Western countries soared over Ukraine.
In October, Russia found Vinatier guilty of gathering information on the Russian military and of violating its "foreign agent" law -- which has usually been reserved for Russian nationals.
"The sentence... against Laurent Vinatier is left unchanged," judge Tatyana Sokolova said at an appeal hearing, an AFP reporter in court heard.
After the sentence was upheld, tears welled in Vinatier's eyes.
Speaking in Russian in a video link from prison, Vinatier had earlier told the court: "I fully admit my guilt. I repent".
The researcher has said he was not aware that he should have registered as a "foreign agent."
The label, which has Stalin-era connotations, has mainly been used against domestic Kremlin critics.
Vinatier worked as an adviser with the Geneva-based Centre for Humanitarian Dialogue and is a veteran researcher on Russia and other post-Soviet countries.
Vinatier has said in court that in his work he always tried to "present Russia's interests in international relations".
"Everything I did in Russia together with its representatives was only for the sake of peace," Vinatier said.
His lawyer Oleg Besonov said the sentence was "too severe" and told the court that Vinatier had two dependent minor children, one of whom is disabled.
The French foreign ministry in a statement repeated a demand for Russia to release Vinatier and repeal its "foreign agents" law, which it said goes against Russia's human rights commitments.
French President Emmanuel Macron has repeatedly called on Russia to free Vinatier, saying that he is unfairly detained and that the "propaganda" against him "does not match reality."
Paris is one of Ukraine's strongest supporters and Russia has singled out France as a particularly hostile state during the conflict.
Russia has arrested several Westerners since its offensive in Ukraine and held several prisoner exchanges with the United States, including the biggest East-West swap since the Cold War in August 2024.
Tensions between Europe and Moscow remain high, while US President Donald Trump meanwhile has warmed US ties with the Kremlin in a dramatic policy shift.
This month, Russia freed a US citizen, Kalob Byers, just a few days after detaining him at a Moscow airport for possession of cannabis-laced gummies in his luggage, a sign of a major turnaround between Moscow and Washington.
Several US citizens previously spent long stints in Russian jails before being exchanged.
Basketball player Brittney Griner, arrested with prescribed medicinal cannabis oil in her luggage, spent 10 months in jail before being swapped, while Wall Street Journal reporter Evan Gershkovich was held in prison for almost one and a half years on "espionage" charges.
