okay, so I mostly wrote a hasty "presumed guilty" opinion (sorry), based on my previous knowledge that he:

• worked for the CIA in GE under a diplomatic cover: I don't know how automatically that amounts to committing espionage (CC art. 272) or maybe unlawful activities on behalf of a foreign state (CC art. 271) or something I'm not aware of)
• was somehow associated with the shady recruitment of a banker: turns out he seems to only be a witness to that (according to himself, which is debated by Ueli Maurer)... don't know either if being a witness to various CIA stuff in GE makes him prosecutable for not denouncing them.

so now I've found this:

By 2007, the CIA stationed him with diplomatic cover in Geneva, Switzerland. His responsibility for maintaining computer network security meant he had clearance to access a wide array of classified documents.

[...]

He described as formative an incident in which he claimed CIA operatives were attempting to recruit a Swiss banker to obtain secret banking information. Snowden said they achieved this by purposely getting the banker drunk and encouraging him to drive home in his car. When the banker was arrested for drunk driving, the undercover agent seeking to befriend him offered to help, and a bond was formed that led to successful recruitment.

source: http://www.theguardian.com/world/2013/jun/09/edward-snowden-nsa-whistleblower-surveillance

However, the story of Snowden's escapades in Switzerland was mainly media hype, Maurer said. The Swiss Foreign Ministry has asked the U.S. embassy in Bern to check what really happened.

Maurer told another Swiss Sunday paper, NZZ am Sonntag, that it was up to the judicial authorities to decide whether or not to launch a criminal investigation into Snowden, but the Swiss cabinet would back such a move as a formality, he said.

source: http://www.reuters.com/article/2013/06/16/us-usa-security-switzerland-snowden-idUSBRE95F09120130616

search results for NZZ am Sonntag snowden maurer, not read yet:

http://www.nzz.ch/aktuell/schweiz/ueli-maurer-fuer-strafuntersuchung-1.18100003

http://www.swissinfo.ch/eng/swiss-president-calls-for-foreign-spy-inquiries/36168066

http://www.handelszeitung.ch/politik/maurer-fuer-untersuchung-gegen-us-spion-genf

I'm running out of time (and frankly out of motivation, I don't care enormously actually, some people are paid for this) but:

1. maybe someone would like to look deeper into that
2. especially: I'm wondering if you can be known to have worked for the CIA, anywhere or even in CH, and then not be worried once you come back to CH... my point is: the CIA's activities are routinely glorified or maybe banalized, but isn't it an organization that no nation (even the US actually, I think by definition the CIA operates abroad) would allow to operate on its soil (unless they are doing something together)?