Administrative costs, early termination of a lease

Hello
I’d have one more question.
I’m leaving my apartment early and I’ve found a solvable candidate who is in process of signing a contract (Vaud).
I’m charged a few hundreds francs for administrative costs for early termination and I’ve found that generally speaking it could be illegal, it was already discussed in this old thread: https://www.englishforum.ch/housing-…rmination.html
However, back in the day I did sign a declaration that I was agreeing to pay such fees in future.
Therefore I am going to pay those fees, but I am wondering, are they illegal or legal given that I signed an obligation to pay them? Just for my peace of mind
The original declaration briefly mentions that administrative fees are due to the fact that the agency needs to announce my apartment on their and other websites, evaluate dossiers so it kind of makes sense, I guess.
Many thanks!

Putting the ad on and reviewing the applications is their job. Could you copy here the point from your contract about the administrative costs?

Well, the law, from ch.ch

If you read your contract carefully, there must be something similar. You could be liable for administrative costs if the agency really put on their ad, etc. However if you presented your candidates instead and they have chosen one (or not but definitely someone was solvent) you're free from any obligations.

I'm also moving out early. I've spoken with my agency about my move asking them for the form or the web address to submit that electronically by my candidates. Their response to that was, yeah sure if you present us a solvent applicant you're free from any obligations, but we reserve the right to put an ad. I've let the people submit their applications. The agency never posted an ad but actually they haven't informed me that they chosen my candidate. I know because I'm in touch with the new tenant. Somehow I've just realized it's been 3 weeks already and no word from the agency. I really wonder what are they up to.

So in my case it turned out that the new tenant "didn't have time" to send back the signed contract, was telling me that he signed it but when I told him that I'm going to talk with the agency because it seems they are misbehaving he suddenly precised "oh I didn't have time to send it back, I'll do tomorrow". Three days later I got the notification from the agency that the contract is signed and I'm released...