I recently obtained some certifications from the Eveche at the following address:
Eveche de Tunis - Chancellerie
4 Rue d’Alger
1000 Tunis R.P.
I requested 7 certificates and enclosed 50 Euros for the service. I recieved the certifications (birth certificates) in about 2 weeks, however I live in Switerland..so not too far from Tunis.
The letter I sent advsied them as to the names I was researching, then I included a table listing all the details from the website; name, year, no. of the record and parish.
I hope this helps!