French president Emmanuel Macron says his glamorous Paris charm offensive on Donald Trump might have changed the US president's mind about climate change.
Mr Macron said "Trump listened to me" on their main point of contention - Mr Trump's withdrawal from the Paris climate agreement - and "said he would try to find a solution in the coming months".
Mr Macron defended his reaching out to Mr Trump, telling the Journal Du Dimanche newspaper: "Our countries are friends, so we should be too."
After a tense, white-knuckle handshake at their first meeting in May, Mr Macron said they gained "better, intimate knowledge of each other" during Trump's visit last week.
The French leader acknowledged Mr Trump's visit was carefully choreographed to give Americans a "stronger image of France" after deadly Islamic extremist attacks damaged tourism.
Separately, President Macron denounced his country's collaboration in the Holocaust, attacking those who still downplay the French role in sending tens of thousands of Jews to their deaths.
Mr Macron said "it was indeed France that organised this," adding "not a single German" was directly involved, but French police collaborating with the Nazis.
Mr Macron, commemorating 75 years since a mass round-up of Jews, dismissed arguments by French far-right leaders that the collaborationist Vichy regime did not represent the French state, saying that is "convenient, but it is false."
At a ceremony attended by Israeli prime minister Benjamin Netanyahu, Mr Macron also pledged to fight continued anti-Semitism.
He called for a thorough investigation into the recent killing of a Parisian woman believed to be linked to anti-Jewish sentiment.
The emotional ceremony at the Vel d'Hiv stadium outside Paris included speeches by French Jewish leaders.
It was at this site during Nazi Germany's occupation of France in the Second World War that French police rounded up some 13,000 people on July 16-17 1942, before they were sent to camps. Fewer than 100 survived.
Pro-Palestinian and other activists protested against Mr Netanyahu's appearance, criticising Jewish settlement policy and the blockade of Gaza.
Mr Macron called it a "natural gesture" to invite Netanyahu.
But the president, who was due to hold separate talks with Mr Netanyahu, told the Journal Du Dimanche newspaper he is "not trying to confuse the subject of the commemoration and Franco-Israeli relations."