I think it's a pure case of numbers.
In college, we learned about the "15% rule". This is the level where the majority population start to feel "threatened". If minorities stay small minorities, they are tolerated, even welcomed. The dynamics change when the numbers increase in a certain group. So observing increased racism in a certain group probably says more about their sheer numbers than any characteristics in their ethnic, national or cultural group.
Asians here, mostly Vietnamese, also have less discrimination. The numbers are lower and with certain exceptions, mostly spread throughout the country. The French say that they were more determined to integrate but I haven't seen that.
I feel, this is what is happening in France. I see it close up. I send my kids to a racially mixed school where no one group "dominates". I live a few miles away where there is a big Moslem population. Everyone's horrified about where we live but I want to say, the school is no different! Meanwhile, we have great BBQ's (Mergez and their maranades!) and everyone is so friendly. They practice their English with me and ask me questions about California. I'll be wearing my Star of David and I have a really Jewish last name but they're totally cool with it all.
I had a Moslem neighbor actually explain to me "I don't wear this because anyone forces me to. It's part of my religion and that's who I am..." It's such a dilemma especially for those who were born and raised in France. They don't want to have to compromise either their French-ness or their religion.
I actually see the culture dissimulating. The families are speaking French together and the children are less religious then their parents. It's also a conflict for young teenagers, like so many in America, Britain and elsewhere, sandwiched between their family's and their country's values. I see young women, wearing fashionable clothes, the latest footwear and a veil to match. They're also rail-skinny and I know what kind of academic pressure young people face here. It can't be easy to meet all those conflicting expectations...
I will explain that France is still a "Latin" country, with a lot in common with Spain, Italy, etc. France tries hard to undermine the system of succeeding thanks to connections. They rightfully should be proud of anti-corruption schemes and a certain equalization where money wont automatically help. The "distance" between the rich and poor is less here and stories abound of poverty-ridden childhoods ending up being the president of the company.
But connections do still have pull here, despite these efforts, connections minorities lack. Academics are highly regarded in a country where a child's future is usually set by the time they are 13 or 14. Academics aren't always valued by other cultural groups in such high regard. I've seen this in my own (all white) family where some religious people raise their children to be honest and hard-working, but don't necessarily push the grades in school.
So those are some other factors in this debate. Whipping off the women's head coverings wont mean that they'll suddenly have higher paid jobs, have fewer children or that those children will do better in school (or show up...) Difficult when there is no job waiting after their hard work... This is what I see bothers the French the most. The busting of their Equal Society myth (which actually can and does often work).
Can't wait to check out that professor's books! Also, thanks for the tip to whomever recommended Amazon.uk!