Based on a survey of the French Biotech SMEs (see annex 1), this article examines localisation effects in the biotechnology sector. It consists of 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, and b) French firms can be grouped into four general types of firm, 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, especially 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 identified for localisation and knowledge spillovers within biotech clusters. The relative effects of the proximity of scientific centres compared to public policy on start-ups is examined.