Black Elk, that is more or less the central idea of the “Vichy France” rule set, part of G40 Balance Mod (and I think Barney incorporated the ruleset into his as well). Game notes follow.
VICHY FRANCE RULE SET
The G40 Balance Mod may be played with or without the following rule-set, which is included for historical interest and fun.
Game Conditions for Franco-German Armistice
At the beginning of France’s turn, if the following conditions are met, the Franco-German Armistice will occur:
1. Axis must control both France and Normandy Bordeaux;
2. France must control Southern France; and
3. There must be no non-French, Allied units in Southern France.
Game Consequences of Franco-German Armistice
French Territorial Control: At the beginning of France’s first turn in which Armistice conditions are met, all originally French territories not already under Axis control immediately change ownership to Pro-Axis Neutrals, except: (1) French Equatorial Africa; (2) New Hebrides; (2) any French territories containing non-French allied units.
With the exception of Southern France (see discussion of “Zone Libere” below), Vichy French territory works the same way as other Pro-Axis Neutral territory–i.e., an Axis player may capture Vichy French territory and commandeer its forces by moving a land unit into the territory during the non-combat phase of his turn.
Fly-over restrictions applicable to other Neutral territories do not apply to Vichy French territory.
Fleet at Toulon: In addition to the change in French territorial control, the Armistice changes control of the the French fleet in sz 93, from French to Pro-Axis neutral. The Vichy French fleet maintains a strictly defensive posture. It may not be moved. It may not be captured by the Axis. The fleet is immediately destroyed if any power, other than the Free French, occupies Southern France
“Zone Libre”: Any Axis occupation of Southern France following the Armistice results in a disbandment of the Vichy French forces and a scuttling of the Vichy French fleet in sz 93. The “Zone Libre” army and fleet will revert back to Free-French control if either: (1) France is liberated by the Allies; or (2) Free-French land forces enter Southern France during the combat-movement phase of France’s turn.
Armistice’s Effect on National Objectives: Vichy French territory is considered “Axis” or “Pro-Axis” controlled for purposes of Italy’s “North Africa” and “Roman Empire” Objectives. Any direct takeover of French Indo China by Japan still negates Japan’s “Trade With America” Objective, even if the territory was already Pro-Axis Neutral.
Liberation of France: The Allied liberation of France effectively terminates the Armistice. Any territory and forces still under Vichy French control (including any surviving fleet in sz 93) revert back to Free French control.