Thank you Ramnat.
I investigate a bit more and I also found that in my log4j.properties (I did copy that in the file at the time I start the project then completely forget about it !!)
I hope this will help other people.
Code:
### Log levels for Hibernate
log4j.logger.org.hibernate = info
#log4j.logger.org.hibernate = debug
### log HQL query parser activity
#log4j.logger.org.hibernate.hql.ast.AST = debug
### log just the SQL
## it respects the "format_sql" and "use_sql_comments" settings from hibernate.cfg.xml
log4j.logger.org.hibernate.SQL = info
### log JDBC bind parameters
log4j.logger.org.hibernate.type = debug
### log schema export/update
log4j.logger.org.hibernate.tool.hbm2ddl = info
### log HQL parse trees
#log4j.logger.org.hibernate.hql = debug
### log cache activity
#log4j.logger.org.hibernate.cache = debug
### log transaction activity
#log4j.logger.org.hibernate.transaction = debug
### log JDBC resource acquisition
#log4j.logger.org.hibernate.jdbc = debug
### enable the following line if you want to track down connection
### leakages when using DriverManagerConnectionProvider
#log4j.logger.org.hibernate.connection.DriverManagerConnectionProvider = trace