Mainly shot at 3.0secs at f8, ISO 200 apart from a few shots that seemed excessively bright when I had to stop down. The camera was on a wireless remote on a tripod so I could shoot without moving the camera and watch the fireworks rather than have an eye glued to the viewfinder. The problem I had was that it was a very calm night with not even the slightest breeze which meant that I got a lot of shots like this ....
... i.e the castle is completely blotted out. The trick is to get one or two good shots of the castle (or whatever) before the smoke arrives or hang around until it has all cleared and merge them carefully in Photoshop masking the chateau image to put back just enough smoke to make it look realistic.
Fireworks will usually overexpose at some point in their short fiery lives and it's a balancing act to try to minimise the overexposure and at the same time capture the colour. Some highlights can be reclaimed in ACR which helps to minimise the overexposure and a little saturation and exposure on the coloured part of the firework does the rest. I generally take a reading on the environment (the castle in this case) and aim for about three seconds on the shutter adjusting aperture as appropriate so that the castle is exposed at an 'appropriate' level. This year the castle wasn't lit up as in previous years so instead of taking a reading from the castle walls I used guesswork and tried to nail the exposure as the first few fireworks appeared.
I'm a total sucker for fireworks (a big kid) and Foix always puts on an impressive display.