Based on a survey of the French population, this study investigates consumer preferences for forest ecosystem services (FES) provision towards efficiency and equity in the context of additionality, and differences in willingness to pay (WTP) for FES between a tax-based and a donation-based payments for ecosystem services (PES) scheme. We show that consumers prefer equity to strict additionality adherence, with this preference being significantly stronger among females. However, consumer preferences are heterogeneous, and respondents with a closer connection to forests express the opposite preference. Regarding WTP, we find no systematic difference between the two payment vehicles, though WTP does vary depending on how respondents perceive potential free-riding. When considering that non-contributors also benefit from a particular PES scheme, a small group perceived this as unfair and reacted by reducing their contribution. A second, significantly larger group interpreted this as an opportunity to contribute to the common good and showed a higher WTP, indicating a markedly altruistic attitude towards FES provision in French society. We conclude by discussing the role of altruism in PES, the dilemma posed by the partial economic and legal incompatibilities of additionality and equity, and the environmental impact of environmental credits when credit buyers do not account for additionality.