We experimentally investigate the impact of information sharing in a common pool resource game. More precisely, we test whether the voluntary disclosure of the decision by a player has a positive impact on the extraction level exhibited by the group compared to the level observed when decisions are compulsory disclosed. We design an experiment composed by three treatments: a mandatory disclosure treatment and two treatments where players are free to choose whether or not to disclose their decisions. The latter differ by the degree of freedom given to players. In the treatment « Voluntary Free Disclosure » players are also free to choose the extraction level that is displayed, while in the treatment « Voluntary Binary Disclosure » if the player discloses h(is)er decision the value displayed is the effective extraction level. We observe that the voluntary disclosure has a positive effect in the social dilemma, measured by lower average extraction levels. However the disclosure mechanism should not allow to self-declare extraction: here it reveals a large tendency to lie leading to an increase in extraction.