1960 to 66 with just short of 700 examples being sold. Citröen took it up after a Norman engineer made one. They were really meant to be used in specialised areas by specialised people, i.e. not for general public use. They weren't very practical - 2 petrol tanks meant not much room in the back, engine in boot as well as the standard one up front, so no boot space. Plus as said, probably more than once 'double the engine double the problems' that would have been less polite in the original French use. Of course the car had a massive power output as a result of the work a mind blowing 26hp - no I haven't missed a zero out.
When one does come up for sale a potential buyer has to have deep pockets as a couple of hundred thousand of our Euros will be needed to pay for it.