A man has been charged with plotting to assassinate President Emmanuel Macron at France's Bastille Day military parade which the French leader is set to attend with US President Donald Trump.
The 23-year-old is a suspected far-right extremist who told investigators he wanted to kill Macron at the July 14 national day parade in Paris, a judicial source close to the investigation said.
He said he also wanted to attack "Muslims, Jews, blacks, homosexuals," the source added.
Police arrested the man at his home on Wednesday in the northwest Paris suburb of Argenteuil after being alerted by users of an internet chatroom where the suspect allegedly said he wanted to buy a firearm.
Three kitchen knives were found in his vehicle and analysis of his computer found that he had conducted internet searches as part of his plot, the source said.
Macron, France's youngest president at 39, invited Trump as his guest of honour for the July 14 parade which commemorates the storming of the Bastille prison in 1789 - the start of the French Revolution and a turning point in world history.
The two men have radically different political views and interests, but Macron appears intent on trying to build a relationship with the US president and has warned against efforts to isolate him at a meeting of G20 nations this weekend.
The July 14 assassination plot recalls the plot of The Day of the Jackal, a book by spy writer Frederick Forsyth in which a hitman attempts to kill former French president Charles de Gaulle, the target of numerous real-life plots.
On Bastille Day in 2002, president Jacques Chirac was the target of an assassination attempt on Paris's Champs Elysees avenue.
The news comes as Macron on Monday promised a "profound transformation" of French politics, proposing to slash by a third the number of MPs, and telling politicians he would call a referendum if they do not agree.
In his first address to members of the National Assembly and Senate since his election in May, Macron delivered a US-style state of the nation speech in the Versailles palace, the former seat of French kings, saying the country must change.
"Until now, we were too often on the wrong track," he said. "We preferred procedures to results, rules to initiative, a society where you live off inherited wealth, to a just society."
He confirmed a plan to implement reform of France's jaded political system, changes first raised during campaigning.
That would include shrinking the number of politicians in both houses of parliament - 577 in the lower house National Assembly and 348 in the Senate - by a third, saying it would have "positive effects on the general quality of parliamentary work".
Macron also pledged to introduce a degree of proportional representation into France's winner-takes-all electoral system.
The move, long demanded by small parties such as the far-right National Front, would ensure "all tendencies are fairly represented", he said.
The centrist president also warned the newly-elected politicians against triumphalism in the face of the "gravity of the circumstances" both in France, which is grappling with a stagnant economy, and in Europe which had "lost its way".
"The building of Europe has been weakened by the spread of bureaucracy and by the growing scepticism that comes from that," Macron said.
"The last 10 years have been cruel for Europe. We have managed crises but we have lost our way," he said, adding that France would help drive a revival of the European idea of "social justice".