With this week’s release of Jira 3.9.3 we have for the first time bundled complete professional translations, in French and German, with the product.
From the Jira 3.9.3 Release Notes:

The French and German language packs have been completely rewritten and are much more comprehensive than ever before. The administration sections of Jira are now completely translated. To achieve this, we recently engaged a professional translation company to provide German and French versions of Jira. These translations are now available in Jira 3.9.3, and we hope they will make your experience with Jira even better.

Thank you, danke and merci to all those people who have provided the previous translations over the years, and also to those who have recently been helping us to check the translations for style, consistency and correctness.
For more information about our ongoing translation efforts, please visit:

Atlassian Translations...