This report presents the results of the process and effectiveness evaluation of the "Avenir sans Tabac" (AsT) program, led by Souffle 64 (Pau). This program is one of five promising projects selected by CIPCA. Its objective is to help young tobacco and cannabis smokers quit or reduce their consumption. Its intervention strategy is based on the motivational interviewing (MI) technique through participation in 1) a Tobacco-Cannabis booth (brief MI) and 2) a group motivational support workshop (group MI) offered at each partner institution in the Pyrénées-Atlantiques region (high schools, vocational training centers). We collected effectiveness indicators from recent cigarette and/or cannabis smokers based on whether or not they were exposed to the AsT intervention (booth only or booth + workshop). Data were collected before the intervention and 3 months after the intervention. We found that participation in a Tobacco-Cannabis booth was associated with a decrease in recent consumption levels among young cigarette and cannabis smokers. The intervention also had positive effects on consumption determinants among cigarette smokers (intention to quit, self-efficacy, perceived peer consumption). The positive impact on the determinants measured 3 months after the intervention was greater when the quality of the EM was higher. For workshop participants (recruited while visiting the booth), AsT had a positive effect on the determinants of use (especially among cigarette smokers) but had no effect on the level of use. Overall, we observed no effect of the program on quit attempts and abstinence. It therefore appears that the Tobacco-Cannabis booth is an effective intervention for reducing consumption. The group workshop, on the other hand, is a potentially promising approach but has not yet been standardized in terms of its implementation; it will therefore require adjustments.