His father, Jean-Baptiste Colbert, was the very effective Controller General of Finance for King Louis, and de Seignelay was the nephew of Colbert de Croissy who had negotiated the Treaty of Dover for Louis. It may have been a coincidence that he was visiting Bordeaux at that time, but his connection to the two main French negotiators of the Treaty of Dover and the routing of funds probably makes his presence relevant.
I also note here a letter in the State Papers dated 30.8.1670 – Anne Thompson to Viscount Conway. ‘…….If you want any Bordeaux wine, I have a relation a merchant in Bordeaux, who will serve you as faithfully as any, and who has supplied your brother-in-law. Remember me to her ladyship.’ Edward, Viscount Conway, was a member of the Irish Privy Council from 1660, and married Anne Finch, sister of Heneage Finch, first Earl of Nottingham, who was made Attorney General in 1670 and became Lord Chancellor in 1673. Anne Finch’s nephew Daniel Finch (2nd Earl of Nottingham) was made Admiralty Commissioner in 1680, and then secretary of state under King William, with special attention to intelligence and Naval affairs.
The Thompsons were uniquely positioned to facilitate the routing of the French funds.
There will have been trusted French merchants on the other side and it is clear that Philibert de Gramont had a role as a French facilitator. Although I have not seen evidence identifying French trading houses or families, it would only have been a very few merchants in France, that enjoyed the same level of (Royal) trust as the Thompsons, and who at the same time could have accommodated the scale of trade enabling the substantial flow of funds. Given the small number of people that Louis had involved in the Treaty details, one might assume that Philibert or his family were involved in the arrangements for the shipment of goods from France. Their personal estates and commercial connections in the south-west of France resulted in them also being well placed to arrange this.
In England those involved were exposing themselves to a certain level of risk. One only has to consider the fact that William of Orange sought, following his arrival in England, to bring King James back to England to face treason charges that included some of the Treaty of Dover’s concessions to France.