We aim to explore the criteria used by teachers of industrial technology contents for implementing work placements (internships). What is a "good" environment for work placements? What is a "good" subject for their internship report? The method is a qualitative survey by semi-directive interviews of teachers in two technological schools ("lycées technologiques") in the suburbs of Paris. One team consists of 5 teachers of mechanics and production engineering for the vocational education of high-level technicians who would design and build automation devices for the manufacturing industry. The other one is composed of 6 teachers of Civil Engineering for the vocational education of high-level technicians who would take part of supervisory staff for construction industry. Results do highlight five dimensions of an "ideal" internship from teachers point of view : (1) It is a technical environment appropriate for the curriculum (2) It is complementary to technology courses; (3) It obeys the institutional instructions so that students achieve their diploma; (4) It is a pedagogical environment ; (5) It makes student realize work process in its globality.