Most French engineering schools have implemented continuing education activities in the 1960s. This movement was linked to the growing awareness of firms that continuing education for engineers and staff was necessary. They were originally quite limited, but have gradually been structured now to represent about 15% of the overall training activities of such schools. Among the first to show interest in continuing education, ENPC organises each year, in France or abroad, around 220 sessions intended for staff belonging to one or several organisations. They represent a linle more than 120,000 trainee-hours and account for nearly 25% of ENPC budget. After analysing the rationale of such an implication of engineering schools in developing continuing education, this paper attempts to sort out specifics of their actions and to define their advantages. In particular it shows how managing continuing education activities in a private-like manner allows for both high scientific, technical and pedagogical standards of proposed programmes and their continuous adjustment to new realities and evolution in the professional spheres involved.