The goal of this study is to test the effect of a growth mindset (GM) intervention with an added implementation intentions (II) protocol on French first-year university students' mindset, creating a new type of psychosocial intervention (GMII). We exposed participants to 3 intervention conditions (GMII vs. GM vs. control), measured mindset via self-reported measures during 3 stages (online questionnaire 2 weeks before the intervention; experimental session with exposure to the intervention; online questionnaire 2 weeks after the intervention), and assessed scholastic performance by testing participants on a subject they had to learn during the experimental session. We found a positive effect of the GMII on participants' mindset (fostering a GM) compared to the other conditions. However, we did not find any link between GM and learning performance. Implications are discussed in light of recent literature and critics on mindset theory and interventions.