We have a new nanny/housekeeper who came highly recommended by trustworthy sources.
We agreed her wage. Then she asked if we would change her contract to show a different, smaller amount and pay that smaller value by bank transfer, then the difference in cash. We said we were happy to pay some of the wage in cash if she needed, (with a receipt issued), but that the contract would show the full wage that we pay her. It turns out that if she declares only the smaller, partial value, she pays less tax. So we worked out what she would "lose" by paying tax on her full earnings and said we would increase the gross salary so that she receives a greater net amount, but pays the full tax due.
I appreciate that she is a relatively low wage earner, however given that this is the law I think we are being reasonable here, even generous, also taking into account that the original contracts had already been signed, and now we will need to draw up new ones (at our cost).
However she is clearly annoyed and gives both of us the stink-eye non-stop. She even asked us to pay the new, higher gross value via the tax-dodge she had asked for originally!