This research looks at design methods for children technologies. It takes a User-Centred Design approach, where the involvement of the users is essential to the achievement of satisfactory products. Categories and Subject Descriptors H 5.2 [User Interfaces]: Prototyping. User-Centred Design, Evaluation/methodology General Terms Performance, Design, Experimentation, Human Factors, Theory. Keywords Informant design, children users, design methods, value for participants.