I can unlock any door in France, is this right?

@Sunny_Rio  No, that's not how things should work.  The only reason I've ever seen this happen is if the lot in question is my sim's home lot.  Even if you're using cheats, they shouldn't be active on a reload.

If you've reloaded and the issue is still present, and you haven't accidentally moved your sims to the tomb lot in question, it's probably a mod issue.  (Some mods can enable cheats as well as adding their own features, so this could be a cheat enabled by a mod as well.)  Try pulling all your mods, as a test.  You don't need to save your progress; just see whether it helps.  If it does, use the 50/50 method to sort through the files.  NRaas mods are fine, they wouldn't cause this, so you can exclude those from the test.

I'm confused now.  I fixed my boat problem by disabling the NRAAS Go Here package, I also remember disabling it for this, seperately, which doesn't make sense.  I can't find anything else I disabled.  I wish I had one of those things called a memory.  Anyway it's working now, I have to solve the puzzles properly.

And you're wrong, it was an NRAAS mod breaking both things.

@Sunny_Rio  GoHere doesn't break tombs.  It's been installed hundreds of thousands of times, refined for over a decade, and this is not feature or a known issue.  So either you borked the settings or you have another mod interfering.

It's the only mod I uninstalled apart from an autosave by Grim, so it must be it.  And the first line in his description says "Adds a slew of options to any door, gate, arch under Lock / Door Options" which made me think it might be messing about.  The door doesn't actually unlock by itself, but I was presented with chained and padlocked doors in the tombs, and when I clicked one there was an option to "unlock door".  When I used it, the chain broke away, then I could click "go through door".  It took me a while to realise I was probably cheating.