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We review studies evaluating tax credit policy for research and development (RD) in France. After examining the factors influencing firms’ use of this policy, we compare these studies with respect to the effect the policy has on several outcome variables. Empirical evidence reveals that past RD values and historical access to RD support schemes significantly affect subscription decisions. This tax policy has a significant additive effect on RD spending, even if it is only guaranteed over the medium term and is most likely for average tax credit amounts. Before 2004, a substitution effect was more prevalent, when tax credit amounts were low. The 2008 reform had a highly positive effect on researcher hiring, while having no effect on the number of patent applications, a result remains to be confirmed by future research. We also raise design and specification issues. JEL Classification: C01; C23; C93; O38.