Product Service Systems (PSS) that create value by sharing or extending the use of products are expected to improve environmental performances of offerings. However, Lifecycle Analysis (LCA) which provides a comprehensive view and assesses the environmental impacts of products is not well adapted to PSS. In this paper, an approach to help the environmental assessment of PSS using LCA during the design process is presented. It compares the environmental consequences of different PSS design alternatives and compares them to those in a hypothetical case of classical product sale replacing the PSS. The paper highlights characteristic requirements of PSS providing intensified use of products for multiple users. Next, a PSS lifecycle model is proposed to perform LCA during the design process. The parametric model constructed will help designers calculate and compare the environmental impacts related to various scenarios of alternative PSS offers. This will facilitate decision-making during the design phase because the PSS lifecycle parameters are identified and linked to PSS design characteristics. With this approach, actions can be easily identified and engaged to improve the PSS solution. A case study on bicycle sharing in the city of Lyon illustrates the approach.