EasyCar expects to take up to 400 Renault Clios on to its fleet that will be based at a new 'exclusively Clio' London site, which could be open before summer.
The internet-booking rental company claims the Clio could cost up to £2 a day less to rent than the Mercedes-Benz A-class and would expand the firm's portfolio beyond premium vehicles.
If the deal goes through it will be the first time EasyCar has not sourced cars from DaimlerChrysler. Since its launch in March 2000, the firm has offered A-classes as well as Smart cars for a limited period.
However, the move does not signal the end of the rental firm's relationship with Mercedes-Benz. A spokesman for the car maker said: 'We have a good working relationship with EasyCar, which will continue.'
Instead, the move is part of a new chapter for the company that will end exclusive supply agreements and introduce competitive tendering. The philosophy of sourcing from more than one manufacturer will help the company grow its fleet by 50% from 5,000 cars to between 7,000 and 8,000 cars.
James Rothnie, Easy-Group's director of corporate affairs, said: 'We are keen to talk to the entire motor industry about how many cars they have got and what deal they can do for us.'
The news comes as EasyCar struggles to meet demand at its Geneva site, which opened in February with 150 vehicles.