Did you select French language translation in customization option during installation? If so, go to System Preferences and change your language to French. If not you can install it later.

When promted to customize installation you also had third party drivers that Zephyrot included. You should have picked nvidia 10.5.2 kexts and 8800-512 nvinject, but you can do it now of course.

go to Terminal and become 'sudo -s'
cd /Volumes/Leopard-10.5.2-AMD-EFI/System/Installation/Packages/

Here you have the packages and you can copy French.pkg and install it

cp -R French.pkg /Users/~yourname/Desktop/ (double click on it later and install)

cd NVidia
cp -R NVidia-Kexts.pkg /Users/~yourname/Desktop/
cp -R NVinject-512.pkg /Users/~yourname/Desktop/

now you have copied these two packages to your desktop, install them both and you'll have working video.
Cheers!

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