This is an easy, 6 step process:
Step 1. Take your South African chenin blancs outside and line them up on the west side of your lawn the east side of your lawn.
Step 2. Buy some German wine...I suggest a strong Müller-Thurgau variety.
Step 3. Line up the German wine on the east side of you lawn.
Step 4. March the German wine across the yard toward the South African wine.
Step 5. Insert white flags into each of your chenin blancs.
Step 6. Enjoy, you now have French wine!
Edit: Honestly, your wines have very little in common besides that they originate from the same grape variety. I would say its easier to find French chenin blancs that change another wine somehow.