The article examines the localisation effects within biotechnology, concentrating in particular on the French case. The paper has two strands of analysis. The first presents a detailed statistical survey of the French biotechnology sector. Among other things, the survey shows that a) localisation effects within France are strong, b) in terms of dependence on local cluster infrastructures (especially universities and related public research institutes), most firms progress from an entry stage in which they are very dependent on local cluster infrastructures, to a mature phase in which their networks become more national/international in focus and c) French firms can be grouped into four general types of firms, ranging from “type 1” growth oriented product firms, to “type 2” niche market players, “ type 3” subsidiaries of larger firms, and “type 4” firms that have been acquired. Localisation effects differ across these firms, esp. across type 1 (international) and type 2 (very localised) firms. The second strand of analysis consists of a review of the localisation and related cluster literature, with implications drawn out for localisation and knowledge spillovers within biotech clusters. It examines the relative effects of scientific centres proximity and compares them to the public policy of start-up creation.