In reply to g taylor:
They started originally in Paris and have been growing steadily, they now spread over a dozen stores all in a 100 yards of each other in the Latin Quarter of Paris. This can be quite confusing as each shop caters for one area of sports-wear. If you go there they will reimburse your parking costs in the nearby underground car-park, if you ask them, of course.
I'm not sure about the tax thing now that Britain is in the EU, I thought it was only for people from outside the EU, but I'm not certain.
They have opened up stores in other places now, including the one you mention, which are all under one roof in the conventional Decathlon way but more specialized. I have a love/hate relation with them - every other time I stomp out vowing never to return but I always do as they have pretty much of a monopoly in Paris.
The staff are often climbers or "sportifs" who one hopes are better climbers than they are sales-staff - often arrogant and dismissive if you don't want to buy the most expensive gear... some are very good though... a bit like all over really.
In Chamonix I find Snell's better, more helpful and competitive for price, but some locals have a grudge against them... not sure why...
Now, getting back to the highly interesting and gripping question of accountancy definitions........ eek!