French Prime Minister Manuel Valls on Monday defended his Socialist government against a stream of criticism of its economic and business reforms during a visit to London.
Valls met British counterpart David Cameron and British and French executives, giving a speech at the Guildhall in the heart of the British capital's City financial district.
French President Francois Hollande was elected in part on a tough line towards the financial sector.
Valls has provoked anger on the left of the Socialist partly by defending stalled reforms to cut charges on companies and to cut public spending, and praising the importance of businesses.
"My government is pro-business!" he told British business leaders in English, quipping: "A French prime minister in the City is an event. A Socialist French prime minister in the City is a revolution!"
In response to rising euroscepticism in Britain, Valls also warned that the country -- and in particular the City -- would "lose a lot" if it were to "turn its back" on Europe.
"France wants Britain to stay in the European Union," he said, calling also for joint action to reform Europe and make it "more intelligible to bring it closer to the people".
"There is a choice that we can and should make together: reform Europe to put growth, competitiveness and jobs back at the heart of its priorities," he said.
Relations have improved between London and Paris since 2012, when Cameron said Britain would "roll out the red carpet" for French executives following the election of President Francois Hollande, who had declared the finance sector "his enemy".
The French prime minister, who arrived in London late on Sunday, began his trip by meeting the French business community in London, home to more than 350,000 French people.
He admitted that France's economic growth had been stuck in a "long breakdown" but said people should not "resign themselves" and encouraged British businesses to invest in France.
- UK eurosceptics influential -
Valls made similar comments after meeting with German Chancellor Angela Merkel in September, and he is expected to take the message to the Netherlands and Luxembourg on October 20.
If negotiations with fiscal hawk Merkel were tough, they threaten to be even harder with Cameron, who is currently trying to appease the eurosceptic wing of his Conservative Party and fend off encroachment from the anti-EU UK Independence Party ahead of next year's general election.
He has already promised to hold an in-out referendum in 2017 on Britain's EU membership if his party wins the May 2015 vote.
The meeting comes amid criticism of France for not doing enough to reduce its budget deficit next year and suggestions made by an EU source to AFP that Brussels is set to reject the new Valls government's fiscal plans.
In contrast, Cameron has pursued a stringent policy of fiscal austerity, despite growth forecasts of 3.5 percent for 2015.
Valls also faces a stiff battle in overcoming "French-bashing", a popular sport north of the Channel.
Andy Street, the director of department store chain John Lewis, last week apologised after saying that "nothing works" in France, and that the country was "finished".
Valls will try and overturn this perception in an interview with BBC's flagship Newsnight programme, to be aired late on Monday.
In the afternoon, Valls is likely to find a more sympathetic ear when he meets the opposition Labour Party leader Ed Miliband.