Here's a list of DELF B2 Vocabulary Topics that you are expected to know.
Current affairs and Social trends:
1. Politics
2. Religion
3. Education
4. Environment
5. Culture
6. Law and order
7. Defence
8. Economy
9. Health
10. History
11. Fashion
12. Work
La politique
La religion
L'éducation
Lécologie
La culture
Le droit et la justice
La défense
L'économie
La santé
L'histoire
La mode
Le monde du travail
DELF B2 Compréhension Orale (Listening)
DELF B2 Compréhension Écrite (Reading)
DELF B2 Production Orale (Speaking)
DELF B2 Production Écrite (Writing)