While HIV testing activity at anonymous and free testing centers (CDAGs) had remained stable since 1995, the number of positive HIV test results has been rising since 1998 among both men and women in Paris. This increase is particularly evident among heterosexuals from sub-Saharan African countries. Other indicators point to a decline in preventive behaviors in recent years. The number of syphilis cases rose sharply in 2000 in Paris among gay men, half of whom were HIV-positive. The results of a survey conducted in Parisian gay venues in 2000 confirm a high level of risk-taking: 30% of respondents with casual partners engage in unprotected anal intercourse. Furthermore, 70% of HIV-positive respondents who regularly frequent sex clubs, backrooms, and video clubs have unprotected sex with casual partners. The number of new AIDS cases has not declined since 1998. More than three-quarters of the AIDS cases diagnosed in the first half of 2001 could likely have been delayed or prevented if the individuals had undergone HIV testing or, had they known they were HIV-positive, had received therapeutic care. People infected through heterosexual contact account for the largest proportion of these AIDS cases resulting from a lack of access to care, and more than one-third of them are nationals of a sub-Saharan African country. (R.A.)