I'd be very surprised if it were legal here rofl!

For me, not sure it would be legal here in France too. Even it is rigidly attached, I suppose the additional axle is still considered as a trailer, as it is not included in the original size of the vehicle, is has wheels ant is attached on the towing point. And in France, you cannot tow 2 trailers. Only circus convoys has the permit to do that when they move from one town to another.

I had one of these cars in the 80s. 6 wheels would be a good safety feature for when the wheels fall off. The build quality and rust was shocking.

This is an Ami Super with a GS 1015cc flat four engine, they were very quick, because the Ami was not a heavy car, only made between '73 and '76.
The ordinary Ami 6 and 8 were 2 cylinder 602cc engines, with slightly better carbs than the 2CV.
An Ami 6 was my first Citroen, I bought it for £55.00 and it seized up on the way home from purchase.But I towed it home and took off the front valance and wings, took out the engine and put new pistons and barrells and a new clutch, and it soldiered on.Very comfortable,very cheap to run and very rare then in the early seventies.All cars suffered with rust in those days.The Ami was a huge seller, I believe it was France's best small car seller between 1961 and 1976,it was made to a price, most of the panels were bolt on, and the chassis's did rust, but for the money the build quality was very good, and as long as they were serviced and oil changed regularly they could be driven flat out all day and still return 35-40mpg, not bad for a 600cc engine! I went on to have Ami 8's , 2Cv's, GS and DS and XM cars,I was a bit smitten with Citroens you could say! Now I am back to Volvo's.

Ami6 was the best selling car only in 1966. For the rest Renault 4, Peugeot 204, Simca 1100, renault 12 and renault 5 took the lead during 61-76