If she isn't the first nonwhite and not the first person of African descent to win the pageant or other beauty pageants in that country then fear of the other can't be too widespread in that society. It's apparent that French society may be tolerant of racial and ethnic diversity but not cultural diversity if she and other nonwhites have won such contests.
I don't think that's true. French believe that there is no other culture but French culture. So even though she is biracial and her mother is from the US, she is still a product of French culture.
What the French fear most is loss of French culture and people who do not assimilate, and they are deathly afraid of Arab French or Muslims.
I also think there is a difference between actually being tolerant of racial or ethnic differences, and thinking "Oh, look at the cute little non-white/biracial girl, she is exotic" without actually having to interact with non-white/biracial people on a day-to-day basis.