New record was measured in southern town of Gallargues-le-Montueux - the previous record was 44.1C during deadly 2003 heatwave.
President Macron and heads of other member states fear Britain could gain advantage over them by undercutting EU environment law.
French president had a 'direct' talk on phone with President Trump after latter announced US will pull out of Paris climate agreement.
So far 17 states, mainly small island and low-lying coastal countries, have ratified the deal reached at the UN climate conference in Paris last December.
French president, the first to sign, said the 28-nation EU should now 'lead by example' and ratify the Paris deal before the end of the year.
The United Nations international climate summit, COP21, opened at Le Bourget close to Paris on November 30th in unusual circumstances. The host country France is under a state of emergency as it welcomes leaders, negotiators and activists from around the world. As Mediapart's environment correspondent Jade Lindgaard reports, a deal at the summit appears to be within reach, but doubts and questions remain about the real direction of the negotiations.
Arrests followed a peaceful protest in which 10,000 people formed 3km human chain along the route of a cancelled march against climate change.
Paris agrees new global climate accord will not be called a 'treaty' and might not contain legally-binding emissions reduction targets.
French authorities accused of abusing post-terror attack state of emergency to curtail protests ahead of Monday's climate conference in Paris.
Private cars were not allowed to drive through centre of French capital between 11am and 6pm in bid to promote cleaner forms of transport.
The call came in a briefing for international ministers attending preparatory talks next week in Paris ahead of December's 190-nation summit.
French climate diplomat Laurence Tubiana says hosts of Paris climate summit will take lead if countries fail to deliver new text by August.
Axa plans to sell €500m of coal assets and triple 'green investments' to €3 billion by 2020 as part of fossil-fuel divestment movement.
French president François Hollande has flown to the Philippines to boost support for a deal in December's key climate summit in Paris.