Electric shock from faucets in contact with running water

Hello, all advice greatly appreciated!

I'm staying in a house in rural France and unable to have an electrician out immediately.

Have been here two weeks. Almost every time I touch the shower taps whilst standing under the running water, I receive an electric shock. Shock is sustained as long as skin is in contact with tap, although severity decreased. At first we thought it cuts on fingers (been doing a lot of manual work) or static. Now realise that is not the case.

Shocks also felt by other members of my group, although not all (the man who normally lives here says he has never, though his female partner has - I am amazed that they continue to use shower without concern).
Shocks also felt in kitchen sink, from dishwasher (when someone had spent a while with tap running) and in bathroom tap.

So, whilst I know this is a serious problem, and potentially very dangerous, I do not quite understand what is going on, and what safety precautions to take until its fixed. Obviously not using the plumbing is the fail safe, but not that practical if it will take a while to fix and can be avoided!

The base of the shower is plastic. I have experimented a little (as there have been times when I havnt felt a shock). After showering for 8 or so minutes (without touching the taps) I stepped out of the shower (walked around for a few minutes wondering how to turn the shower off) and then turned it off without making contact with the running water. Felt no shock.

Questions (from reading around internet):
Is it likely that the plumbing is being used as ground and there is an electrical fault somewhere? Causing the 'ground' water pipes to not be ground?

If that was the case - would it be that the water was effectively live - thus making the showering person live - and thus completing the circuit to ground when touching the faucet?

And if THIS is the case - and the shower pipes were carrying a potentially deadly load - would simply making contact with the water be enough to receive a shock - or would it only happen when completing the circuit by touching the taps?

I have also read that it could be a fault with the electricity/ water supplier? Again - any advice on how to do a safe check myself of this would be really useful

Thanks for any help you can offer! Or suggest any safe tests I can do - things I can check so I know who to call out!

I have time but no access to resources outside of what is in the house!

Thanks again!