AFAIK, it's not legal to grow in the Rhone Valley. The major areas (Rhone, Bordeaux, Burgundy, Loire, Champagne) are tightly locked down under law. Most of the remainder of France is pretty open.
I'm probably getting too technical here, but it is
not illegal to grow Durif, Marselan, Pinot Noir, Nebbiolo, Touriga Nacional, or Cabernet Sauvingnon in the Rhone or any other wine region. However, it is illegal to put any of those grapes into a bottle which claims to be a "Cotes du Rhone" (or Bordeaux, Burgundy, Loire, or Champagne) and that is simply because it is not one of the many red or white grapes which is accepted for inclusion in a wine with that designation. Similar restrictions on what wine grape varietals may be added, apply to wines labeled Bordeaux, Burgundy, Loire, Champagne (and the same goes for other famous European wine regions, but generally doesn't apply to the new world where varietals are generally listed on the labels). But again, you can grow whatever grapes you want in those regions, but when you bottle them you simply could not label them as being from that region.
For most wine grape growers that would be
financially ruinous, as there is a ton of cachet which is associated with wines which are labeled Burgundy, Bordeaux, Champagne, Rhone, or Loire or the various smaller villages or regions within those broader labels (sub-appellations in U.S. lingo, AOCs in France, DOCs or even better DOCGs in Italy).
But, if you have a huge reputation or ego or cash to burn, you might grow whatever you like (or blend in whatever you like), and sell it as de-classified wine (
Vin de France in France fka Vin de Table;
IGT or even Vino da Tavola in Italy).
So there is a movement towards freedom from old winemaking restrictions in France, Italy, Spain and other old world countries with restrictive laws, just look at this marketing for Vin de France:
Vin De France | go.sevenfifty.com
A huge success story here are the now widely celebrated as "
Super Tuscans" (generally blends of Sangiovese with Bordeaux varietals) now fetch huge $ and have huge cachet, but they had to use the Vino da Tavola label when they first came out. This eventually led to the creation of a new, higher designation, IGT for such wines:
SUPER TUSCAN: This useful but unofficial term emerged in the 1970s, to describe a particular set of high-quality Tuscan wines which were precluded from claiming DOC or DOCG status because they broke traditional Italian winemaking norms (foreign grape varieties were used, and the wines were often matured in small, new oak barrels). Several of these wines earned global recognition and astronomical price tags - hence 'Super Tuscan'. Originally these wines had to be labeled as Vino da Tavola because they contravened the stringent, tradition-focused DOC laws. This situation ultimately led to the creation of the IGT category, with its relatively relaxed production rules.
Similarly, one of the oddest wine regions in the old world, Ribera Del Duero, allows way more 'foreign grapes' than it does other well known Spanish grapes, and that all goes back to Vega Sicilia's huge success:
In 1864, Eloy Lecanda y Chaves, a Bordeaux-trained Spanish winemaker, established Vega Sicilia east of Valladolid. He planted his vineyards with Tinto Fino, as well as the Bordeaux varieties Cabernet Sauvignon, Merlot, and Malbec, and went on to create artful wine blends that had significant commercial success. Vega Sicilia remains one of Ribera del Duero’s most notable producers today.
The appellation pertains almost exclusively to red and rosado (rosé) wines. To be recognized as DO, red wines must contain a minimum of 75 percent Tempranillo, though most are made with 100 percent. Blends may contain up to 25 percent Cabernet Sauvignon, Merlot, or Malbec. No more than 5 percent Garnacha or Albillo, altogether, may be added. Rosado wines must be made with a minimum of 50 percent of the region’s authorized red varieties. For the new white wines category, DO regulations required that at least 75 percent of the grape used is Albillo.
https://daily.sevenfifty.com/regions/ribera-del-duero/