Fillon is the leader of the centre-right Front National, which has been running the country since its founding in 2004.
Fillon’s election as the country’s prime minister on Sunday was seen as a victory for populism, a rejection of globalization and an attack on free trade.
He has repeatedly criticised the European Union and criticized EU President Donald Tusk for failing to do enough to stop migration.
His anti-immigration stance has also led to criticism that he is too soft on Russia.
“He is a nationalist, but not a fascist,” Marine Le Pen, leader of France’s far-right National Front, said in an interview on Sunday.
“He doesn’t care about anything.”
Le Pen has been at the centre of a scandal over his ties to the National Front since she won the 2015 presidential election.
She has been accused of using her political connections to gain support for her father, Jean-Marie Le Pen.
He denies wrongdoing and says the allegations are politically motivated.
Fournier’s appointment was announced after an outcry from business and labor unions.
“We will make Fourniers appointment as Minister of Commerce, Industry and Trade as soon as possible,” Le Pen said.
“I think this is a step forward in terms of ensuring that all our businesses can thrive in the European market, in the international market, and the world.”