Hi Rouen,
As far as I know you can no longer dive at Franskraal, thanks to perly poachers and a force that cannot police it, plus some inept lawmakers, but I digress...
The dive ban runs from Gansbaai harbour to the mout of the Ratel river well past Die Dam. Which means you can only dive to the right of Gansbaai harbour. I only dived it once, but think it is much like the rest of the coast - large chunks of empty kelp, with some fish in a few hotspots. You will find the usual suspects in the kelp - hotties, galjoen, john borwn, butterfish. Every now & then you might get lucky iwth a steenbras or a geelbek, but that would be the exception. One of our party that day saw a brute galjoen, so it's worth a look. Let us know if you go how it was.
Cheers,
Tony