The analysis used data from quarterly reports on inmate populations; information from computerized searches of court records, prison registers, and inmate criminal records; and data from preliminary court hearings and sentencing records. Results revealed that foreign nationals accounted for 6 percent of the total population of France and 16 percent of those brought in for questioning; 25 percent of inmates are foreign nationals. The sharp rise in illegal immigration resulting from a change in immigration policy accounts for the increase in foreigners arrested. In addition, foreigners tend to be arrested for offenses that traditionally receive prison terms, particularly thefts and violent offenses. Therefore, caution should be used when interpreting statistics on criminality by foreign nationals.