I think that the car is a Isotta Viotti modified by Ets. Vermeulen :
"This car was ordered in 1935-1937(??) by Count Rossi of Martini, Italy from Carrosseria Viotti in Turin. When the importer of Isotta Fraschini in the USA went bankrupt, the remaining chassis were sent back to Italy. Count Rossi bought two of them (typo 8B) and had them send to Viotti in Torino who was asked to produce a convertible and a coupe to be used as publicity cars for Martini. The coupe received a futuristic coachwork .... The coupe was used for a whole string of classical manifestations (tours of Italy , Mille Miglia etc.) Before the second world war, the Martini subsidiary in Brussels was opened. They could use a publicity car and the coupe was send to Belgium. The car was used at numerous events like the 24 hours of Franchorchamps, the races at Zolder, etc. At the end of the fifties, the car was technically outdated, the cable brakes did not stand up to the modern demands and it was decided to place the coupe on a more modern chassis. Unfortunately they did not find a chassis that was large enough to take the coachwork and they opted for a chassis of a Lincoln Zephyr V12 of 1937. The job was performed by the "Ets. Vermeulen" in Schaarbeek, near Brussels who altered the wings and bumpers (they used pieces from a Lincoln 1949 amongst other things) "