France's National Rally party leader Marine Le Pen took to Twitter to express her anger with the court order.
"I thought I had been through it all: well, no! For denouncing the horrors of Daesh (Isis) with tweets, the "justice system" has referred me for a psychiatric assessment. How far will they go?!" she said.
"This regime is really starting to be frightening," Le Pen added.
Le Pen noted that, contrary to French media reports, the procedure was not customary.
The National Assembly (lower house of parliament) of France in November 2017, at the request of the Nanteré Prosecutor's Office, deprived Le Pen of parliamentary immunity in connection with the publication on Twitter. If the French court finds her guilty, the leader of the party may face up to three years in prison and a fine of 75,000 euros.
*Daesh (also known as ISIS/ISIL/IS) is a terrorist group banned in Russia