And to be fair it was common in both France and Italy.
I must admit that back in 1996 I was appalled, whilst trying to buy a bankrupt restaurant in Paris from a Mandataire Liquidateur (Liquidator), it was made clear to me that although my offer was the highest and one of the most credible, unless she got FF 50000 in cash (£5000 at the time) in a brown envelope, then I would not get the attribution.
The Mandataire Liquidateur is a court appointed official. I couldn't believe my ears.
I was successful in buying the place, and I personally never paid her the baksheesh.
She did get her cash though. Ahem.