How can I mitigate large tax bill?

As a single man with no living relatives, my estate will be distributed to friends. Are there any ways to mitigate the draconian death duties of 60% on my French estate?

If your estate were invested in certain kinds of investment product (such as a suitable assurance vie policy) and you rented property instead of owning it, there could be significant savings for the eventual beneficiaries. 

You would be best advised to see a qualified financial specialist to consider the best options for your circumstances.