It was also my experience that French police - 'ordinary', gendarmerie or CRS would appear in great numbers without an obvious reason. Sometimes they look like Asterix and Obelix, sometimes, like on Tour d'France finale, somewhat more, er, serious.

Tha 40% unemployment figure is probably right for some narrow groups (say, young blue-collar Africans) in some neighborhood. I think I noticed that Paris and surrounding is losing manufacturing jobs (while probably gaining white-collar ones), which particularly affects groups with lower education level. For example, Renault is dismantling its huge manufacturing facility on an island on the Seine near Sevres (photos, map). Cisco was supposed to build its European HQ there, but now somebody else is developing an office complex.

I worked for several months in Saint-Denis, consulting at SNCF (national railroads) IT (OK, I did not live there). While parts of the town are somewhat run down, government seems to be making large efforts at revitalization. It is nothing similar to devastated inner city districts or appaling high rise housings as found in some American cities, as some news reports would like us to believe. In general, I would say that city-owned apartment complexes function rather well (though perhaps not quite as well as, say, in Vienna), although recent events seem to suggest that the layer of normalcy I observed was only veneer-thin. There are also many new office complexes in suburbs (in Saint-Denis I noticed, for example, a huge Gaz de France facility, Siemens tower etc), but judging by Metro traffic very few locals work in them.

I think that myth of lazy French is very much exactly that, myth. Granted, we Europeans generally think that if our government is not providing us with decent health care, education and social safety net then we don't need the government, but Europe is producing Airbuses, Bimmers and TGVs, after all. I was usually putting 50-hour weeks in SNCF, but I was rerely the last to leave our office.

Returning to your original question, I am affraid that most countries with high uneployment rate and wide gap between richest and poorest segments of society are tinderboxes similar to France. Of course, French heavy-handed assimilation policy does not help (try to send a document to a governmet office in Breton, Basque, Arabic or, for that matter, German).