Sorry for being a bit late.
No worries!

I also have a bit of a problem with translating two words:
1. "Mayor's Office" - I see that you've written it with capital letters. Is it refers to any other bat/maxis reward?
It refers to my previous BAT, the "SFBT Mairie":
French:
MairieEnglish:
Mayor's OfficeGerman:
Buergermeisteramt (replaced the umlaut with "ue")
Polish:
Urzad Miasta (not sure, copied from the corresponding LTEXT)
2. City Palace - similarly to Akallan, I have problem with it. "pałac miejski" means literally a "city palace", but it would just mean a very representative building in a city. However, if it is to mean a specific institution, like a town hall/city hall/headquarters of city government, it would rather be "urząd miasta" (oficial name), "ratusz" or "magistrat" (more relevant to the building itself).
The former:
French:
hotel particulier (o with circumflex)
English:
city palace (Wikipedia suggests "townhouse", but Andreas rightly considers that as misleading)
German:
StadtpalaisPolish:
?_____
Modding the Hotel Cail is altering the Modding of my Mairie to a very large extent. There are two further LTEXTs, which need to be changed. I just know, how to change the respective French texts.

(To prevent further confusion: Hotel Cail is the name of a specific
hotel particulier in Paris, which acts as mairie/mayor's office of the 8th arrondissement, and was model of the BAT, I am talking about all the time

)
Mairie (example; no translations needed, as they already exist):
A Mayor's Office for #city#
Urzad Miasta #city#
The Mairie is not available.
Requirements: . . .
Urzad Miasta niedostepny.
Wymagania: . . .
Hotel Cail:
The Hotel Cail for #city#
[Polish translation required] #city#
The Hotel Cail is not available.
Requirements: . . .
[Polish translation required]
Wymagania: . . .
_____
These are the French texts of Akallan. Dear French native speakers, I guess, you're content so far? Silence equals consent!

Maire [name of mayor], [name of city] est devenue une ville respectable. Le conseil municipal est parvenu à la conclusion que le mairie modeste ne répondait plus à vos exigences élevées en tant que maire d'une métropole en développement et a donc approuvé la construction d'un hotel particulier [this will link to the building] en tant que nouvelle résidence à #city#. Si vous souhaitez distribuer la charge administrative sur plusieurs épaules, une utilisation en tant que mairie est possible car le bâtiment peut être replacé aussi souvent que souhaité.
L'Hotel Cail est le bureau du maire, mais peut également servir de mairie d'arrondissement des grandes villes.