Does anyone know where to get car seat covers etc. around Tunis ?

Plenty of shops will cover the seats of your car very professionally. I have better knowledge of the south where there is a little workshop who does this to a high standard, with the logo of your car, but there must be such shops around Tunis too.

Your best bet is to ask any car rental business as they all cover the seats of their cars.

Of course you will ask at least at two or three different places as sometimes some people will tell you they will introduce you to the right workshop where they actually ask for a commission that will end up being charged to you by the shop.

Much appreciated

Hi There,
There is a bunch of shops selling seat covers in Rue Chedli Kallela in Tunis.

small cities.go to down town or carrefour or geant

Sunblock glasses adhesive films are available in Tunis but there legally non authorized.  The police are allowed to take temporarily your car ID "carte grise" and make you pay 10 TND after making sure you removed the adhesive sunblock film. But car curtains are authorized. Such accessories are available in the supermarkets (Carefour, Géant...). Standard size car seats covers are also available. But if you want customized specially made ones than I can help.

kind Regards 
Brahim HAJLAOUI