I did a read lock with my table 'Client', after i did an update in my table 'Client' just to see the error message. So here's what I did:
mysql> LOCK TABLES Client READ;
Query OK, 0 rows affected (0.00 sec)
mysql> UPDATE Client SET pays = 'Suisse' WHERE id = 4;
I expected the error message: ERROR 1100(HY000): Table 'Client' was locked with a READ lock and can't be updated
But i have this message: ERROR 1100 (HY000): Table 'adoption' was not locked with LOCK TABLES
'adoption' is another table in my database ! I hope you will help me, thank you