In the field of learning design, IMS has standardized EML, the Educational Modeling Language proposed by OUNL. However, it remains to be seen whether it will be widely adopted. Moreover, evolutions of IMS-LD and competing models are proposed by several teams. The objective of this workshop is to confront the approaches (models, tools, methodologies) through modeling and implementation experiences of collaborative learning activities. To facilitate the comparison, a case study is proposed. The outcomes of this workshop will be discussed during the panel "Learning Design of Collaborative Learning Activities: languages, models and tools".