There are occasionally local tax rates that differ depending on the type of traveller, e.g. no tax for business travellers, €2/night for tourists. I've mostly seen it in Germany.
It's generally written somewhere, but on aggregation sites like hotels.com and booking.com it seems the hotel can't alter the advertised price directly.
> A city tax is imposed by the city of Cologne. Business travellers with proof of business-related travel are exempt from this tax. For more details, please contact the property using the information on the reservation confirmation received after booking.
> An effective city/local tax rate of 5.00 per cent will be charged
It's generally written somewhere, but on aggregation sites like hotels.com and booking.com it seems the hotel can't alter the advertised price directly.
Example: https://www.hotels.com/ho119759/maritim-hotel-koln-cologne-g...
> A city tax is imposed by the city of Cologne. Business travellers with proof of business-related travel are exempt from this tax. For more details, please contact the property using the information on the reservation confirmation received after booking.
> An effective city/local tax rate of 5.00 per cent will be charged