When using Stash and JIRA in French (and other alternative languages) you can't transition JIRA tickets from within Stash and are greeted with the following error message;

Unable to render embedded object: File (Screen Shot 2015-07-21 at 09.56.39) not found.

It appears that because the workflow transitions are not translated in JIRA, Stash can't match up the transition names during the REST call.

For example if you try to close the JIRA ticket in Stash with the resolution as Doublon, because in JIRA this is still registered as Duplicate you receive the error;

Le nom de résolution 'Doublon' n'est pas valide

The REST call used to transition the issue should use the none translated transition value - for the default workflow at least.

Workaround

To work around this you can modify the resolution values in JIRA so that they match the French equivalents in Stash.