 The DNA tests would be paid for by France under new amendments |
Supporters of the move - part of a tough immigration bill passed by the lower house - say it will speed up the process for genuine applicants.
They argue that 12 other European countries have similar rules.
Critics have attacked the law as racist and question the use of genetics as a basis for citizenship.
Last-minute concessions
The legislation asks immigrant family members older than 16 to take a test in their country of origin, demonstrating a good knowledge of French language and values.
Applicants also have to prove that their family in France could support them and earn at least the minimum wage.
Immigration Minister Brice Hortefeux made some last-minute changes to the bill before the Senate vote on Wednesday.
The tests will now be paid for by the French government, to prevent any possible discrimination against those who cannot afford the tests.
In addition, they will now only examine maternal DNA, to prevent paternity disputes arising from the tests.
