This YouTube video will introduce the procedure for first-time application, renewal, and replacement of a damaged or lost Tunisian passport with the Tunisian Embassy in Beijing.
Passport application form (make sure to fill it in both Arabic and French):
Note: If your occupation changed from a student (at the time of getting your ID card) to work, then you can still submit your passport renewal application, but you will need to update your national ID card when you go to Tunisia)
The procedure for updating the data on your national ID card is available here (in Arabic).
Form to request the return of the old passport:
You should receive a letter of receipt of the new passport from the embassy as follows:
For the consular fee, please refer here.
If you are not in Beijing, you will need to mail the application to the Tunisian Embassy in Beijing. You may find the mailing address here.