President Emmanuel Macron has made the bill a key plank of his second term but has been embarrassed by the support it drew from his arch rival, Marine Le Pen's far-right National Rally party, and referred the legislation to France's Constitutional Council to check if it complies with the constitution.

The Council is due to announce its verdict on Thursday.

The bill includes migration quotas, obstacles to family reunification and delays to migrants' access to welfare benefits, as well as articles cancelling automatic birthright citizenship and making it easier to deport non-French nationals.

"When we look at the French constitution or the way in which the head of state or many in positions of power speak, it's [about] equality, but that is in strong contradiction to these policies," Ashwini K.P., Special Rapporteur on contemporary forms of racism, racial discrimination, xenophobia and related intolerance, told Reuters in a phone interview at the weekend.

On Sunday, tens of thousands of people across France took part in the latest protests against the bill, denouncing it as a betrayal of French values, although opinion polls indicate public support for the legislation.

'MARGINALISED COMMUNITIES'

Ashwini K.P. expressed particular concern over the proposed restrictions to social welfare for migrants, fee hikes and the introduction of a refundable deposit for foreign students, saying these would greatly "impact marginalised communities".

She said she hoped France's Constitutional Council would make amendments.

The Elysee and French interior ministry did not respond to a Reuters request for comment.

Some of the tougher elements in the bill were added to win the support of right-wing lawmakers after Macron, a centrist, lost his parliamentary majority last year but they have caused unease among some of his more left-leaning lawmakers.

Ashwini K.P. said she would focus on discrimination in France this year, given the influence of far-right groups there, incidents such as the police shooting last year of a teenager of North African descent that prompted nationwide riots, and discrimination against Muslim women wearing the hijab.

(Reporting by Layli Foroudi; Editing by Gareth Jones)

By Layli Foroudi