With 3.4 million full-time equivalent jobs, trade as a whole (wholesale, retail and automobile trade and excluding crafts industries) concentrates 20% of the non-financial market sector. It also represents one fifth of non-financial enterprises (companies and sole proprietors) in number and a little less in value added. Between 1997 and 2007, hourly labour productivity grew by 3% annually. Where did this growth in productivity, which contributes three quarters of the development of the sector's value added, come from? Aggregated analysis over the decade 1997-2007 reveals the structural effect of the firms that came and left: nearly half of the gains in hourly productivity (45%) are due to the arrival of new companies that replaced the less efficient ones departing. Two factors could explain this improved performance: innovation and organisation as a network. Innovation promotes the contribution of net inflows to global productivity. With the available data, the impact on productivity of belonging to a network can only be grasped by comparing the property of an integrated network to all the other forms of organisation. The effect seems very limited, but this result must be re-examined by using more complete data from future statistical operations.