"All of the candidates for the parliamentary elections will be designated by the end of this week," Ferrand told the Europe 1 broadcaster.
At the moment, only 14 En Marche! nominees have been announced, but the party is planning to have candidates competing in all 577 constituencies. In January, Macron said he would like to have female candidates in half of the "winnable" constituencies.
En Marche! was founded by Macron in April 2016 a few months before he resigned from his post of the minister of the economy. The party does not currently hold any seats in the French parliament.
The legislative elections are scheduled to take place on June 11 and June 18. The candidates have to officially announce their intention to run on May 15-19.