This article estimates a hedonic pesticide price model using 151 pesticide products linked to more than 39 chemical families over the period 1996 to 2006 in France. To take into account the chemical family as well as the unbalanced structure of the panel a nested error component model is estimated. This approach embeddes the successive components of the error term into the preceding component thus capturing the unobservable heterogeneity. Based on the predicted prices, the decrease of indices in 2001, corresponding to the setting of a toxicity-tax, suggests that pesticide turnover and innovativeness is more important than toxicity-tax effect. Acknowledgement :