If you edit a random record of Accounts, Contacts, Opportunity writing in the description field a sentence containing an accented character (àèìòù for example) you can see
Be careful and create backups of the files you change, before messing with them.
You might need a Quick Repair and Rebuild (or even Symfony cache:clear from the command-line) to make changes effective. If you do it from the command-line be careful not to break permissions and ownerships.