There are a number of official maps of cities.  The most obvious one is Frieburg, but I think all of the Nation books have one as well.  And Charouse is in Montaigne.

I'll be frank.  The city maps in first edition sucked.  They were terrible.  As someone who loves city maps in RPG (though rarely uses them), there isn't a single city map in a single sourcebook that I can point to and say, "they did a great job."  Even (especially) once they brought in the d20 audience.  The maps are terrible.

Here's the official map of Charouse.  It's a pretty good representative of the whole.

Now compare that to a completely amateur rendering of Paix.

I mean, it's pretty disgraceful.  I'm not sure what the maps for L5R looked like, but they couldn't have been worse.

No, I would suggest just doing a pinterest search for fantasy city maps and finding some you like and relabeling them for your own purposes.  Everyone will be happier.

Tom