Istanbul: Turkish President Recep Tayyip Erdogan’s lawyer has lodged a complaint against a former French diplomat accusing him of inciting an assassination of Turkey’s leader, his spokesman confirmed on Monday.

The move follows comments by Philippe Moreau Defarges about the outcome of the April 16 referendum on controversial constitutional changes that will tighten the president’s grip on power.

Defarges, now a senior fellow at the French Institute of International Relations, said all legal paths to challenge Erdogan had been shut off and that the only two options left were civil war or assassination.

In the referendum the ‘Yes’ camp won just over 51 per cent of the vote, a narrower-than-expected victory, but Turkey’s top election board last week rejected opposition calls to annul it after complaints of vote-rigging.

Defarges said on French broadcaster BFM on Saturday that Erdogan’s strengthened powers would lead “only to catastrophe”.

“There will either be a civil war or another scenario ... his assassination,” he said — though later apologised for the comments.

Huseyin Aydin, a lawyer representing Erdogan, said in a petition to an Ankara prosecutor that the comments were not a simple expression of opinion, but were “clearly instigating the crime in question”, the state-run Anadolu news agency reported.

He said the comments showed how far the hostility against Erdogan had reached in the West, and suggested Defarges should undergo checks for his mental health if he ever came to Turkey.

“And if he is in good health mentally, his alleged links with the outlawed Kurdistan Workers’ Party (PKK) or US-based Muslim cleric Fethullah Gulen blamed by the Turkish government for orchestrating the failed July coup should be investigated.”

Erdogan’s spokesman Ibrahim Kalin confirmed the legal action during a press conference in Ankara, saying, “We will do our best not to legitimise such fascist approaches.”

He said Defarges’s comments would have “legal consequences” and the researcher had to face them.

The comments went viral on social media, with a senior Erdogan adviser calling on the French institute to revoke Defarges’s fellowship.

“Former French diplomat openly calls for assassination of President Erdogan. @IFRI_ should terminate his fellowship, apologise,” Gulnur Aybet wrote on Twitter.

“What would be the reaction if a former diplomat & senior fellow at a Turkish think tank called for the assassination of the French president?”

Defarges on Sunday offered his “sincere apologies” for his remarks.

“Some of what I said was clumsy and might have been wrongly interpreted,” he said on Twitter.

But Kalin said the apology was “not enough,” and that “this is not an issue that can be taken lightly.”

He added: “This is a test for Europe. Let’s see how they will react.”