thousands of foreign fighters flowing into those countries with a social media campaign unprecented. recruiting people from around the world, including in the u.s. and europe. more than 1,500 french citizens affiliated with isis, one-quarter of the european total. this past july, a french-speaking member of isis appeared in this video threatening the group will bring slaught tore france. >> there have been a relatively large number of individuals from france who have traveled to syria, joined with the groups in the conflict there, and then have come back home. just as extreme or even more extreme than before they left. >> reporter: this "new yorker" magazine article described a region called department 93. a large area of disaffected african and arab populations who feel cut off from french society. according to the article, timates are 60% of french prison inmates are muslim. prime targets for jihadists. >> one of the challenges that the french government and the french people will face in the days ahead will be to ensure that hate crimes aren't committed against people who had noth