postgresql – Cannot drop databae in postgres

I would like to unserstand why I am not able to drop a database from cmd:
I execute the command: drop database if exists <db_name> but the result is as below:

postgres=# drop database testV5;

ERROR:  database "testV5" does not exist

knowing that the database exists:

postgres=# l
                                  Liste des bases de donnÚes


   Nom     | PropriÚtaire | Encodage |  Collationnement   |    Type caract.    |    Droits d'accÞs
  testV4   | postgres     | UTF8     | French_Canada.1252 | French_Canada.1252 |
  testV5   | postgres     | UTF8     | French_Canada.1252 | French_Canada.1252 |
  postgres | postgres     | UTF8     | French_Canada.1252 | French_Canada.1252 |
  template0| postgres     | UTF8     | French_Canada.1252 | French_Canada.1252 |          
  template1| postgres     | UTF8     | French_Canada.1252 | French_Canada.1252 |         
    

Can anyone explain that please ?
Thanks in advance.