It's always hard to get enthusiatic about an invoice. But this humble document does provide some useful information:
- It confirms Établissement Charles Gautherot as the producer of the Super Leader brand of derailleurs.
- It gives an address in Dijon for the business.
- It confirms that the Super Leader Route model was available in 1943.
- The trade price of 75 Francs in 1943 would be roughly equivalent to 50 Euros today, giving an estimated retail price of around 100 Euros. Derailleurs were not cheap.
- The sentence at the bottom of the invoice might translate as something like "price controlled from September 1939 with the last increase authorized on 6/9/41 by order No. 1170 of the Ministry of Finance". War time seems to mean that the prices of vital items like bicycle derailleurs must not be allowed to run riot.
- If the exigencies of war mean that prices must be controlled, they do not seem to mean that valuable engineering resources cannot be deployed on making derailleurs. In Britain most of the bicycle industry was taken over for war work as early as 1939, and, in Birmingham, the Cyclo Gear Company was certainly not allowed to use valuable skilled workers, lathes or steel to make anything as peripheral to the war effort as derailleurs.