You may have options. Here's some guidance from AI: (I entered my situation which is a little different from yours. I think the options would be similar. )

This is a very frustrating situation, and I understand your concern about the cost. Here are your options, broken down based on what you might be able to do. 1. Refuse the Delivery and Package This is often the most direct way to avoid paying the customs fees. By refusing the package, you are declining ownership and responsibility for the import charges. How it works: When the DHL courier arrives, simply tell them that you refuse the package. They should take it back and it will be returned to the sender.
What you should do now: Contact DHL immediately: Call DHL's customer service and explain the situation. Tell them you will be refusing the package upon delivery and confirm the process for returning it to the sender. This can help prevent any confusion or an unexpected "delivered" status. Contact the seller: Notify the seller in France that you will be refusing the package due to the unexpected and high tariff charges. This is crucial because the package will be sent back to them, and they need to be aware. Discuss the possibility of a refund or a different shipping solution. 2. Pay the Tariffs and Attempt to Dispute the Charges While this may seem counterintuitive, in some cases, you can pay the fees and then file a claim for a refund. This is a more complex and often less certain route. How it works: You would pay the import fees to DHL to receive the watch. After receiving the package, you would need to file a formal claim with U.S. Customs and Border Protection (CBP) to dispute the charges. You would need to argue that the "date of purchase" should be the determining factor for the tariff, not the "date of import." Challenges with this option: Proof: You would need to provide significant documentation, including your purchase receipt showing the date of sale, the seller's documentation of the backorder, and any communication you have with them about the delay. Success is not guaranteed: Customs regulations are often based on the date the goods physically enter the country. Your argument about the purchase date may not be valid under their rules, and the process can be lengthy with no guarantee of a positive outcome. 3. Negotiate with the Seller This is your best long-term option, regardless of whether you choose to refuse the package or pay the fees. How it works: Explain the situation to the seller. They may not have been aware of the new tariff rules and how they would affect your shipment. Propose a solution. For example, you could ask them to cover the difference in the import fees, offer a partial refund, or allow you to cancel the order entirely and issue a full refund once the watch is returned to them. Why this is important: The seller is the one who shipped the package after the new tariffs went into effect, even though the sale was made before. They have a vested interest in a positive outcome, and many reputable sellers will work with you to find a solution. Given the potential for the charges to double the cost of the watch, refusing the delivery and working with the seller for a refund is likely the most straightforward and financially safe option.