for many years (i.e. since 1985) I have carried the tools with my classics in military bags either army surplus or repro. Something like this https://www.sofmilitary.co.uk/1908-small...anvas.html
Recently I've acquired an old French leather plumbers tool bag from a brocante shop so you could try and look at brocante shops who buy their stock in France
Like this one but then an old one of high quality leather https://nl.rs-online.com/web/p/tool-bags...lsrc=aw.ds
or look here https://www.ebay.co.uk/b/Vintage-Tool-Ba...7022849995
Recently I've acquired an old French leather plumbers tool bag from a brocante shop so you could try and look at brocante shops who buy their stock in France
Like this one but then an old one of high quality leather https://nl.rs-online.com/web/p/tool-bags...lsrc=aw.ds
or look here https://www.ebay.co.uk/b/Vintage-Tool-Ba...7022849995