In Paris, at STD clinics, the number of syphilis cases has declined steadily since the 1980s. In 2000, a rise in the number of cases revealed an epidemic among gay men. To address this epidemic, public health initiatives targeting healthcare professionals and gay men were implemented (May to September 2002). The impact of these initiatives was assessed in terms of syphilis screening, syphilis transmission, and patient care. Syphilis screening activity was evaluated in the 11 Parisian CDAGs (Consultations for Anonymous and Free HIV Testing) (May to September 2002) and in a network of Parisian clinical laboratories (2001–2002). The impact on syphilis transmission was assessed using syphilis surveillance data (2000–2002). Sales of Extencilline® (2.4 million units) in Parisian pharmacies were selected as an indicator to estimate the care provided to people with syphilis by private-sector physicians (2001–2002). In the 11 CDAGs, 23,756 questionnaires were collected, and 6,841 were sampled for analysis. The overall prevalence of syphilis among those screened was 1.10% [95% CI 0.96–1.24]. Among CDAG patients, factors independently associated with a positive syphilis test were being over 30 years of age, being homosexual, and being HIV-positive. In the 40 participating Parisian laboratories, the number of TPHA/VDRL tests performed increased by 23% between 2001 and 2002. The number of primary and secondary syphilis cases diagnosed in the surveillance system doubled between the first and second quarters of 2002. Sales of Extencilline® 2.4 MUI, which remained relatively stable from January 2001 to May 2002, rose sharply as soon as the initiatives began. To address the syphilis epidemic, public health interventions included providing information on syphilis to healthcare professionals and encouraging syphilis screening among at-risk individuals. An evaluation conducted near the end of the interventions showed a positive impact on screening rates. Over time, further interventions will be necessary to control the epidemic. (R.A.)