M-learning (mobile learning) can take various forms. We are interested in contextualized M-learning, i.e. the training related to the situation physically or logically localized. Contextualization and pervasivity are important aspects of our approach. We propose in particular MOCOCO principles (Mobility - COntextualisation - COoperation) using IMERA platform (Mobile Interaction in the Augmented Real Environment) covering our university campus in which we prototype and test our approach. We are studying various mobile learning contexts related to professional activities, in order to master appliances (Installation, Use, Breakdown diagnostic and Repairing). Contextualisation, traceability and checking of execution of prescribed operations are based mainly on the use of RFID labels. Investigation of the appropriate training methods for this kind of learning situation, applying mainly a constructivist approach known as "Just-in-time learning", "learning by doing", "learning and doing", constitutes an important topic of this project. From an organizational point of view we are in perfect symbiosis with EPSS - Electronic Performance Support System [12] and our objective is to integrate learning in professional activities in three ways: 1/ before work i.e. to learn about coming actions, 2/ after work i.e. to learn about past actions to understand what happened and accumulate experience, 3/ during work i.e. to master the problem just-in-time We are also studying an appropriate relationship between the just-in-time M-learning approach and preliminary training performed in a serious game approach based on typical action scenarios.