Joseph Breham is suing bin Salman - who just ended a visit to France as part of a three-day official trip - for his role in launching Saudi Arabia's now three-year-old campaign of airstrikes in Yemen against the Iran-backed Houthis.
The lawsuit claims that bin Salman, who also serves as defence minister, knowingly targeted civilians.
At least 10,000 people have died since Saudi Arabia began airstrikes in March 2015. There are also up to one million suspected cholera cases in the country, which the UN has dubbed the "world's worst humanitarian disaster".
Breham, representing the Legal Center for Rights and Development, told AP that France has the jurisdiction to investigate the case as it was filed while bin Salman is on French soil. But he acknowledged that diplomatic immunity bars the crown prince from arrest.
Speaking to reporters in Paris on Tuesday, Saudi Foreign Minister Adel al-Jubeir called the lawsuit "ridiculous".
Tuesday, Lebanese Prime Minister Saad Hariri tweeted a photo with bin Salman and Morocco's King Mohamed VI in a suprise meeting in the country.
The Saudi crown prince concludes his visit to France with further discussions with President Emmanuel Macron ahead of a gala dinner at the Elysee Palace.
Much of the prince's visit has focused on deepening cultural ties with France, with Saudi officials drawing on the country's expertise to set up a national opera and orchestra.
But activists have mobilised to keep attention focused on French weapons exports to Saudi Arabia and rights abuses in the kingdom.
Three out of four French people believe it is "unacceptable" for France, the world's third largest arms exporters, to continue selling weapons to Saudi Arabia, according to a YouGov poll.
This article has been adapted from its original source.
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