I draw your attention about Barthélemy Massiac
I have translated this text from a spanish web
"This guy was a French military engineer who served Portugal. He came to Latin America, en route to Europe, to sell slaves and goods. It was captured by a privateer and brought to Buenos Aires. This posed as Catalan and drew maps of the city, where he remained for over two years. He was later sent to Spain. They released him, then wrote a memoir of his trip to Rio de la Plata and proposed to the government of Louis XIV to invade the territory described by him. The Colbert paid some attention to the project and sent a detailed questionnaire about Buenos Aires, Massiac said. Finally, the plan was forgotten. But the text drafted by De Massiac became a document of great historical importance. For many, this is one of the most compelling testimonies on the seventeenth-century Buenos Aires. Written between 1660 and 1662, during the sojourn of the engineer in the small town, this report presents, in addition to physical descriptions of the place, an elaborate project to conquer the territories ranging from the Rio de la Plata to the mines of Potosi, which past would then form part of the reign of Louis XIV"