All over the world, deaf people claim their own culture and identity through their language: the sign language. According to the 2006 “United Nations Convention on the Rights of Persons with Disabilities” (UNCRPD) and the article 21 about “Freedom of expression and opinion, and access to information”, member states need to recognize and promote the use of sign languages. Currently in museums, mediation adapted to deaf public is generally sign guided tours (by deaf guide or hearing guide with interpreter) or sign videos. But visits are rare, separate, on reservation, videos do not concern every exhibit. How to improve this mediation offer and make sign language more visible? Can we increase deaf people engagement to think about inclusion in museums? We conducted a two-year public study among the deaf public of Toulouse, France. The city is considered as the capital of deaf people and the heart of Sign Language activism. But paradoxically in the city’s museums, accessibility is not more developed than elsewhere. We present the method developed, the pitfalls and the results. Beyond, transforming museums for inclusion, seems to us, requires bringing together the hearing and deaf public in the same mediation offer. We describe our pathway of universal mediation based on understanding and learning means of communication from our fellow citizens (currently perceived as impaired). Firstly, a written mediation including sign language in each museum label. Secondly, sign guided tours by language levels combining cultural mediation and sign language learning. We believe museum could become this communication space.