The Ile de France region has passed a new rule meant to favor French businesses. It follows other similar rules seeking to limit the number of foreigners on public construction sites.
Officials in the Paris region on Friday passed the "Small Business Act," which they say is aimed at ensuring more public building contracts go to French companies.
The bill also contains what is known as the "Moliere clause" - named after the famous 17th century French playwright - which forces firms working on publicly funded building projects to use French as the working language.
"This clause is necessary and targets foreign companies who come with their teams, without any of them speaking French," the region's vice president, Jerome Chartier, said after the rule was passed. "These companies need to improve."
Anger at EU rules
EU rules on publicly funded projects prevent governments from discriminating against companies on the basis of their country of origin. French officials have often criticized the rules, arguing they put locals at a disadvantage by allowing companies to use cheap laborers from other European countries, often in eastern Europe.
Critics of the Moliere clause, meanwhile, argue that it essentially discriminates against newly arrived foreigners by making it more difficult for them to integrate. They also say the rule is too difficult to enforce.
Other French regions, including Normandy, Hauts-de-France and Auvergne-Rhone-Alpes, have introduced similar bills.