Final answer:
Countertrade best exemplifies the scenario where a French firm agrees to buy Spanish tomatoes to sell its chocolates in Spain. The amount France would give up depends on the terms of the agreement.
Step-by-step explanation:
The term that best exemplifies the situation where Le Chocolat du Monde, a French firm, is allowed to sell its products in Spain only if it agrees to purchase Spanish tomatoes in return is countertrade. This type of trade involves a reciprocal agreement where goods are exchanged for other goods, rather than currency transactions. It is often used to facilitate trade between countries that may have currency restrictions or to balance trade between companies or nations. Regarding how much France would need to give up in terms of tomatoes to gain from trade, and how much in terms of green beans, this would depend on the specific details of the countertrade agreement, such as the relative value of the goods exchanged and the terms negotiated by the entities involved.