Even when they read the details of the system played by Bacherich-Ghestem, their opponents didn't feel they understood it—and no wonder. One of the basic principles is the "relay" bid, which doesn't mean anything except a request for more information from partner. Most often, the relay bid as used by the responder consists of a bid in the suit just above the opener's suit.
Opening bids of one club and two clubs are artificial; one club is semiforcing, two clubs forcing to game. But while two diamonds is a strong bid, two hearts and two spades are weak. One no trump is strong—18 to 21 points—but three no trump is weak and shows a long minor suit.
No-trump responses give some idea of this system's complexity: any response but two clubs or four clubs is a transfer bid, requiring opener to rebid in the next higher suit. Four clubs asks for aces; two clubs asks for a five-card suit. Without a five-card suit, opener bids two diamonds and if responder then makes a new relay bid of two hearts, opener bids his four-card suit or suits thus: Two spades shows four spades; three hearts shows four hearts; three spades or three no trump shows four of each major; three clubs shows four clubs and four hearts; three diamonds shows four diamonds and four hearts. Having dutifully shown four-card suits, if responder makes a new relay—cheapest possible bid in next suit—opener bids his shortest suit!
There are further refinements of the method, each step more bewildering than the last. I think we can be grateful that, for the most part, the French relied on natural bidding to win. Bridge is complicated enough—there is no need to make it inexplicable.