The primaries are especially relevant given that its winner will be crucial to sustain support against the far-right National Front party. Polls show that the party led by Marine Le Pen – who wants to quit the EU - will get the most votes in the first ballot to the presidency.
In an attempt to convince French expats to have a say in the center-right party nomination and increase his odds of winning, Francois Fillon, one of the five contestants, spoke at the Royal Institution in London Thursday evening.
"France needs a deep transformation," he told an audience of French expats.
Former prime minister of France, Francois Fillon has a tough battle ahead. He is only placing third in the forecasts for the center-right nomination and votes from French expats could be a significant boost.
His main opponents are Nikolas Sarkozy and Alain Juppe, also a former prime minister, who bookmakers believe is the most favorite to represent Les Republicains.
"France needs to decrease the cost of labour, not only on low qualified jobs, but on all kinds. France sees precisely a decrease in the quality of its economy because of those politics," Fillon said to the London audience.
Fillon wants to make France more investment-friendly.
"[Tax on capital revenue] is 30 percent in Germany, it is 60 percent in France. How can we have French investors with those conditions?," Fillon said.
It is also among his policies to restore trust in the public authorities following the terrorist attacks, to reduce the number of deputies in parliament.