I'd be a little careful removing ten year old stickers from a black car. Depending on how the paintwork has been looked after you may find there has been some sun fading over the years. Hopefully not, but when you remove the stickers you may find you'll have slightly different coloured sticker shaped patches on the car. A lot will depend on the paint type used to spray these Renaults, but I've seen it happen on some cars.
As for removal I'd suggest a kettle plugged in the garage, switch it on and when it's boiling use the steam on the edges of the decals. The steam will soften the glue and make the decals more flexible to peel off. At ten years old they may well be a little brittle now. Keep turning the kettle on repeatedly to keep the steam coming. The most important thing is to ensure you do it carefully and not to rush it. I'd use the kettle/steam method rather than a heat gun. A paint stripping heat gun is likely to be too fierce a heat. Good luck with it.