You have several options. Option one is at the application level. You can do this in the system.web section of the web.config file:
<globalization culture="fr-FR" uiCulture="fr-FR" />
Another option is on the page:
<%@Page Culture="fr-FR" Language="C#" %>
or downstream:
Thread.CurrentThread.CurrentCulture = new CultureInfo("fr-FR");
See http://support.microsoft.com/kb/306162 for more details .