A French citizen in Israel has been charged with smuggling weapons to Palestinians for financial gain.
Israeli security services say the man, Romain Franck, 23, worked as a driver for the French consulate in Jerusalem.
He is accused of transferring dozens of guns between Gaza and the occupied West Bank, using a consular car to avoid Israeli security checks.
He appeared in court in southern Israel, along with several Palestinian suspects.
A French embassy spokesman said France was working closely with the Israeli authorities on the matter.
Israel's Shin Bet security agency said Mr Franck was arrested in February.
He is accused of transferring 70 pistols and two assault rifles. He is one of nine suspects arrested so far.
Shin Bet said Mr Franck acted for his own financial gain.
The agency said he received the weapons from a Palestinian employed at the French Cultural Center in Gaza and transferred them to a third person in the West Bank in the course of five trips.
"This is a most serious incident, cynically exploiting the immunity and additional privileges extended to foreign representatives to Israel," the agency said in a statement.
A spokesman for the French embassy in Tel Aviv told the AFP news agency: "We take this case very seriously and are in close contact with the Israeli authorities."
Mr Franck worked at the consulate as an "international volunteer", a status that allows young adults to gain work experience abroad.
By Yolande Knell, BBC News, Jerusalem
At the Erez border crossing, foreign journalists, non-governmental organisation workers and Palestinians with permits go through rigorous Israeli security screening.
However, diplomatic privileges allow consular workers to drive in and out of Gaza with virtually no checks.
Shin Bet accuses Romain Franck of taking advantage of this arrangement to smuggle weapons.
Little is known about Mr Franck, who held a junior position at the French consulate.
However, a Facebook page set up in his name shows a young man similar in appearance to the one in the photograph published by Shin Bet.
A post from January 2017 says the account holder is leaving for Jerusalem. He writes: "It's the big day, departure to a new adventure."
Another caption says: "Feeling good in Palestine".
Israel has long tried to prevent arms reaching Palestinian militants.
Israel and Egypt maintain a blockade around the Gaza Strip to prevent weapons smuggling and attacks by Gaza-based militants. There are also tight security measures to stop arms getting into the hands of militant cells in the West Bank.