Changed default database collation only.
You must alter all tables in you database.
A,Change collation of table columns by EM.
B,Faster would be
1.Generate script for all database by EM to text file without Generate drop existing option.
2.Open this file in notepad
3.Replace collation strings French_CI to French_CS (use your collation)
4.Copy create database part to QA and change database name and run
5.Switch to new database
5.Copy create tables part to QA and run
6.Use DTS wizard to copy data from your old database
7.Copy all remaining code to QA and run
8.Switch your databases by sp_renamedb (old->bak,new->old)
Note that server can use different collation from database. TempDb uses collation of model.