So after google translating it, I get the following:
The "De Witt" distribution plan was an attempt to distribute the Southern Netherlands prior to the war of devolution. The plan was developed in 1663 by Louis XIV and presented to council member Johan de Witt of the Republic of the Seven United Netherlands. This so-called "de Witt" plan included the division along the Ostend-Maastricht line, north of the language border. Northern of this line would fall to the Republic and be south of the line for France.
With the following map:
If I understand it properly, the proposed border to the Dutch side is the dotted one starting with "1663", with an Ostend-Maastricht line.
This would mean that:
- France get most of historical Flanders, except the main cities of Bruges and Ghent (north of the line, Bruges is probably the "B" on the map).
- France would get most of Brabant, including Bruxelles, but not Mechelen. Basically, France would get the today province of Flemish and Walloon Brabant, the Netherlands would get the Antwerp province.
- France would get all the southern French speaking and catholic provinces: Artois, Hainaut, Namur and Luxembourg.
- The United provincew would get an extended Flanders of the state, with Bruges and Ghent, a good chunk of Brabant including Antwerp and Mechelen (I know at this point it was a separate province but I simplified a bit there). And the strategic fortress of Maastricht.
If I understand this correctly, this is the plan proposed by Louis XIV to the Dutch. One can easily see how the response was "this is too much land for the French", as indeed this was clearly the case. What could have been a counterproposal from the Dutch, instead of them joining the Triple Alliance against the French?