Complex system developments are more and more collaborative. Collaboration strategies largely depend on the development context at modelling, instantiation or enactment time. To put collaboration in action, we propose collaboration process patterns to define, reuse and enact collaborative software development processes. In this paper we describe the definition and application of collaboration patterns. Our patterns, inspired from workflow patterns of Van der Aalst, are described in CMSPEM, a Process Modelling Language developed in our team in 2014. In this paper, we briefly describe the CMSPEM metamodel and focus our presentation on two collaboration patterns: Duplicate in Sequence with Multiple Actors, Duplicate in Parallel with Multiple Actors and Merge. The approach is illustrated by a case study concerning the collaborative and representative process “Review a deliverable”.