We study in this paper the effect of the type of information provided by an ecolabel. For this purpose, in the framework of a model of vertical differentiation, we compare the effects of a partial information label (Type I) and a complete information label (Type III) on firms' profits, industry profit, consumers' surplus, environmental damage and social welfare. A partial information label indicates that the environmental quality of a good exceeds some given threshold. The authority issuing a partial information label chooses its labeling criteria while maximizing the social welfare. A complete information label indicates the exact environmental quality chosen by firms. We prove that while a partial information label always improves the social welfare and deteriorates the green firm profit compared to a complete information label, the comparison between the two types of ecolabel in terms of the brown firm's profit, the industry's profit, the consumers surplus and the environment depend in a non-obvious way on the marginal cost of quality and on the environmental sensitivity to quality.