There is in Europe a trend for privatisation and commercialisation of technical extension services for agriculture. At the same time, extension is supposed to support the contribution of multifunctional agriculture (MFA) to rural development. This article proposes an analytic framework to test whether performances of commercial extension enable to enhance the effectiveness of intangible investments in MFA context. Empirical investigations were realised about technical extension for cereal production in Ain (France) and Zeeland (Netherlands). It appears that [A] private extension providers hardly invest in R&D relevant to MFA context; [B] some farmers who contribute to MFA may lack technical knowledge when provided by commercial extension.