Hi Paul
Have a look at this thread
http://www.survivefrance.com/forum/topics/re-pointing-cellar-interior-wall-advice-please
I made a few comments myself about the mix and methods of pointing.
I endorse Edward Byrne's comments strongly. If you use cement in pointing for stonework the pointing will be harder than the stone and when the wall moves (as it inevitably will) the stones may crack and/or the pointing fall out. Lime mortar (NHL) is softer than the soft limestone or sandstone used in most of SW France.
You can mix the correct colour by using different colours of sand and once you have the recipe it is easily reproduced. I haven't used tints but I suspect they are much trickier to manage and get repeatable colour on successive batches. The mix is important as is the time you mix. Use a mixer it is very hard to mix for 15-20 minutes by hand. Don't buy the expensive premixed mortar (most has cement in it and it costs x5-6 using separate sand and DHL)
Take you time and be careful on the ladders!