The DILF, DELF and DALF are diplomas awarded by the French Ministry of National Education to assess language skills of people whose first language is not French.
They are designed by the Centre International d’Etudes Pédagogiques (CIEP), a public body part of the French Ministry of Education. Recognized world-widely, they are often requested in French universities for foreign students or in international companies looking for bilingual employees.
They are consistent with the six levels of the Common European Framework of Reference for Languages (CECR).
You can find a simplified description of each on this blog:
You can check as well the official brochure (French and English) from the French Ambassy website