Launched in 2015 after the January terrorist attacks in France, the Seriously project is the result of a twofold objective for the think tank Renaissance Numérique: (1) Taking action to restrain the hate dynamic that spreads in our societies and is particularly visible on the Internet; (2) Creating and offering tools that encourage the active participation of civil society and citizen. In addition to the law and reporting tools, the Seriously project is a method as much as a tool to defuse online hate speech. The website www.seriously.ong offers objective arguments and behavioral advice to Internet users. It offers an intuitive user experience built around three sets of functionalities: factual elements, experts’ advice, and resources suitable for the digital format. Developed by Renaissance Numérique, the Seriously project has been all along based on a collaborative approach with national and international actors who demonstrated a broad knowledge and experience of these stakes: associations, academics, educational actors, platform providers and institutions. This collaborative approach has been notably materialized by creating governing bodies and realizing awareness actions at grass-roots level. After two years of work, the Seriously project has been identified as one of the best practices to face hate on the Internet. As reflected in a recent report, entitled “Countering Violent Extremism and Radicalisation that Lead to Terrorism: Ideas, Recommendations, and Good Practices from the OSCE Region”, published in September 2017 by the Organization for Security and Cooperation in Europe.