How to say "see everything there is to see" in casual French?

Question

{I said}: Je serai de retour quand j’aurai regardé tout ce qu'il faut regarder dans cette ville !

I wonder if this is the French equivalent of the following English construction.

I'll be back once I see everything there is to see in this city!

There is a nearly identical expression in German, with the „zu“ having the same function as the "to".

Du siehst mich wieder, wenn ich in dieser Stadt alles gesehen habe, was es zu sehen gibt!

But I don't suppose it sounds idiomatic to do the same with French and apply « à », as in « il est à noter que ... », to this particular sentence, does it?

Je serai de retour quand j’aurai regardé tout ce qui est à regarder dans cette ville !

Answer 1

The most natural way of saying it would be:

... quand j'aurai vu tout ce qu'il y a à voir...

With:

• voir over regarder
• tout ce qu'il y a à + verb

Answer 2

This is another very natural way to say that, despite it being more informal :

Je serai de retour quand j’en aurai fait le tour

Answer 3

I guess a more idiomatic way to say it would be :

... quand j'aurai tout vu de cette ville.

Without the repetition, you imply that you mean "everything possible" within this context (i.e. everything you would be able to see).

I join @AlexisLeGal on his answer. The expression "faire le tour de" is often used in various context and means that you have (or need to) covert the subject.

Il est nécessaire de faire le tour de la question.

Could be translated by

It is necessary to deal with every possibility.

But it's a very "context-wise" expression.