The study we have conducted of existing cloud platforms shows that their operating requires the use of specific and proprietary APIs. This PaaS providers' policy is hampering the interactions between different clouds. If appropriate solutions are not considered, this issue would for instance slow down the democratization of clouds federation and cooperation. In this paper, we propose (i) a unified description model that allows the representation of applications independently of the targeted PaaS for their hosting and (ii) a generic PaaS application provisioning and management API (called COAPS API). Our proposed solution applies the separation of concerns principle by separating the provisioning and the management API from the defined description model. We motivate our solution with real use case scenarios and an implementation to show its feasibility.