While in Togo he was ordered in April 1889 to proceed to Walfish Bay in command of a small German force, which included his broher Hugo*, and secure the German presence in the territory that is now Namibia. Upon his arrival in June 1889 he immediately went into the interior to deal with various opponents of the German occupation and to stop the infiltration of arms and ammunition into the territory, making his headquarters at Otjimbingwe. In the process he and Hugo made the first compass traverse from Walfish Bay to Windhoek, where he founded a settlement and erected a fort that came to be known as Die Alte Feste. Their observations formed the basis of a German map of Damaraland and Hereroland, Karte der von Hauptman und Lieutenant von Francois gemachten Aufnahmen in dem südwestafrikanischen Schutzgebiete (1890, 1:300 000). Probably as a result of his surveying experience in the tropics he made the mistake of using a rectangular grid for the first ten sheets of this map; nonetheless it formed an important basis for later cartographic work. Meanwhile Curt travelled eastward to Lake Ngami in January to March 1890 to meet opponents to German rule. From December 1890 to March 1891 he and Hugo travelled to the Waterberg and on to the Okanvango. He then made three journeys southwards to Namaland and eastwards to the Kalahari between August 1891 and May 1892, and founded the town Swakopmund in September 1892.

Both Curt and Hugo made detailed geographical notes and astronomical observations on their many travels, covering most of present Namibia. Curt published a number of papers on his travels. Some appeared in the Mitteilungen aus den deutschen Schutzgebieten: On his journey to the Okavango River (1891), a journey between Windhoek and Gobabis (1892), his travels in the Kalahari (1893), and on the coastal region between the Swakop River and Cape Cross (1893). Others were published in the Deutsche Kolonial-Zeitung: On the landscape around Windhoek (1891), a travel report (1891), and a report on a journey in the southern part of the territory (1892). He also submitted to the German government two proposals for the settlement of German farmers in Damaraland, in October 1890 and November 1892.

Curt was an intelligent and popular officer who carried out his duties with vision. In 1891 he succeeded Dr H.E. Goering as imperial commissioner of the territory and moved its administration from Otjimbingwe to Windhoek. He was promoted to major in 1893, and given the title of landeshauptmann. He was actively involved in both the development and politics of the territory but in March 1893 started a war against the Namas under Hendrik Witbooi which led to his replacement by Major T. Leutwein. He left the territory for Germany in September 1895. Thereafter he travelled in east and north Africa and settled in Berlin. In 1899 he published a book, Deutsch-Suedwest-Afrika. Geschichte der Kolonisation bis zum Ausbruch des Krieges mit Witbooi, April 1893, which presented a detailed account of his term of office in Namibia. This was followed in 1900 by two more publications dealing with the wars in the territory, and in 1905 by another on the same topic.

In 1897 von Francois married Amalie Gertrud Margaretha ('Margret') Meyer, with whom ha had four children. Later he moved to Zernsdorf, where he died.