The French postal service, La Poste, plans to order 10,000 electric delivery vehicles, which it says are far more economical than normal cars or vans.
La Poste has been testing eight French electric vehicles since 2005
The state-run service is inviting tenders from European manufacturers for the first batch of 500.
"There has never been such a big order [for the vehicles] in the world," said French Industry Minister Francois Loos, quoted by the AFP news agency.
La Poste wants to reduce its 70m-euro (£48m; $95m) annual fuel bill.
La Poste has been testing eight French electric vehicles since 2005, made by SVE - a firm owned by the defence group Dassault and vehicle manufacturer Heuliez.
"According to our tests, it is six times cheaper to run an electric vehicle than a diesel vehicle," said La Poste chairman Jean-Paul Bailly.
La Poste believes the change will also cut emissions of the greenhouse gas carbon dioxide (CO2) by four tonnes per vehicle annually.