I completely agree, we're sorry for the incorrect information. You've got two alternatives to fix this:
a) Manually update the ext-lang-fr.js file to correct this or b) include the following code at the beginning of your app.js file: Ext.apply(Ext.util.Format, { thousandSeparator: ' ' });
Both options will instruct the Ext.util.Format class to use the correct character. I've refunded your x-credits for this ticket since it's caused by an issue with the framework files.