The mcSquared European project aims at studying Social Creativity among pedagogical resources designers and Creative Mathematical Thinking in their users, through technology, namely a creative e-book software infrastructure and resources called " c-book units ". This article focuses on a study carried out in the framework of this project in France experimenting such a c-book unit and highlights a particular obstacle created by a didactical contract effect related to creativity in the French mathematics classroom: high achieving students perform well on content related to an official assignment but have difficulties engaging in unusual creative problems. The article concludes on possible ways to circumvent it in order to foster the unleashing of mathematical creativity in all students.