||Oyster farming is the main aquaculture activity in France, where Pacific oyster (Crassostrea gigas) is spatially cultured from the English Channel to the Mediterranean coasts. Oyster growth performance monitored along French coasts are widely heterogeneous among culture sites and over years. Many studies have been carried out to understand the effects of environmental factors on oyster growth and physiology, by using bioenergetics growth models. However, most of these studies were site-specific. As an example, the model developed by Barillé et al. (1997), which was extensively specified with more than 50 parameters, was validated in the Marennes-Oléron Bay, but cannot be successfully applied to other culture sites without re-estimating parameters or re-formulating some processes. In that context, our study aims to develop a generic growth model, i.e. a model than can be applied in various contrasted environments with a constant set of parameters. We used the DEB model designed for the Pacific oyster C. gigas (Pouvreau et al., 2006; Bourlès et al., 2009) based on the DEB theory (Kooijman, 2000). The resulting oyster-DEB model is built on 10 main DEB parameters with some extra parameters to consider specific bioenergetics of C. gigas. Only one DEB parameter, i.e. the half-saturation coefficient Xk which depends on food quality and therefore on ecosystems, was calibrated for each site in order to evaluate the generality and the limits of the model. The results of simulating oyster growth are presented herein by using the oyster-DEB model in several French ecosystems: Arcachon, Marennes-Oléron and Quiberon bays along the Atlantic coastline, Thau Lagoon in Méditerranée, and the Baie du Mont-Saint-Michel and the Baie des Veys in the English Channel. Applying DEB model in contrasted environments allows to explain oyster growth variability among rearing areas according to food quantity (e.g. chlorophyll a, phytoplankton abundances) and quality (phytoplankton species), as well as seawater temperature. The variability of spawning events among sites is also successfully simulated according to the spawning processes implemented in the oyster-DEB model.