The assembly process planning has been the subject of extensive scientific work, mainly due to the multiple aspects involved from geometrical matters to operational research concerns. However, very few issues about assembly technique selection are addressed. The aim of this paper is to propose a method to select an assembly technique for each joint of a product and to allocate geometrical tolerances accordingly. This is achieved by solving a multi-objective optimization problem to minimize the cost and the non-conformity associated with the assembly plan. The potential benefits of the method are illustrated on a case study representing the assembly of a simple mechanical structure.