Introduction - A national smoking cessation E-intervention, called Tabac Info Service (TIS), was developed in France to provide an adapted web and mobile application support to smoking cessation for all adults smokers, with or without chronic diseases, who want to stop smoking. This paper presents the study protocol of the evaluation of the program. The primary objective of this evaluation is to assess the efficacy and efficacy conditions of eTIS. The secondary objectives are to 1) describe efficacy variations in regard to user characteristics, 2) analyze mechanisms and efficacy conditions of eTIS, through variations of use, social or environmental contextual factors likely to influence the efficacy of eTIS, and the behavior change techniques (BCTs).

Methods and analyses - The study design is a two-arm pragmatic randomized controlled trial including a process evaluation with at least 3000 participants randomized to the intervention or to the control arm (current practices presented in a non-interactive website). Inclusion criteria are: Adults, Smokers with an information and consent form completed, Getting a smartphone and using mobile applications, wanting stop to smoking in short, medium or long terms. The exclusion criterion is the refusal to participate in the study. The primary outcome is the point prevalence abstinence of 7 days at 6 months later. The secondary outcomes are: the point prevalence abstinence of 24 h at 3 months later, the point prevalence abstinence of 30 days at 12 months later, number of quit attempts during the study, progression of stages within the program (changes and duration in each stage). Data will be analyzed in Intention to treat (main analyze) and per protocol ways. A logistic regression will be carried out to estimate an OR [95% confidence interval] for efficacy. A multivariate multilevel analysis will explore the influence of patients' characteristics, social and environmental context, conditions of use and behavior change techniques on results.

Dissemination -The findings of this study will allow us to understand and characterize the efficacy of eTIS, and conditions of its efficacy, underlining psychological, sociological, environmental and contextual factors, which could influence the efficacy of this type of intervention on smokers. These findings will be disseminated through peer-reviewed journals, national and international conference presentations and public events.

Inclusion Criteria:

• adult smokers
• with an information and consent form completed
• agreed to participate in the study
• get a Smartphone and be willing to use applications
• wanting stop smoking (in short, medium or long terms).

Exclusion Criteria:

• refusal to participate in the study