Switzerland Air Labels(?)

I found these two in an old album in poor condition. They are printed on very poor quality paper which has deteriorated over time, now being quite brittle. They look to be cancelled in red ink with a Swiss Cross inside a four lobed shape and have denominations in Centimes with the Inscription in French and English.

I cannot find a reference to them and wonder if someone out there can point me in the right direction.

International Air Meeting, May 31 to June 1, 1925. You have both values of the "Suisse-Europe Centrale" issue. The same two values are also found with "Suisse-France" in the bottom tablet.

According to Sanabria, there were 5,000 of each of the four issues printed.

The inscription is not in English

SBK puts these under Flugspende-Vignette, ##15-16. Zumstein doesn't number them but shows the slogan cancel that appears twice on vayolene's example, along with a second boxed two-line handstamp, "GENEVE-PARIS".

Great information and it certainly provides the when and the where for the labels. But what was the function of the issue? They obviously were purchased so what service, if any, was being paid for? Or was it simply a fund raiser for the Organization hosting the meeting?

Now thats one really precise postmark on a stamp (the second stamp posted in original post), pure perfection

Does anyone know the meaning of "Cmes" on the lower right corner? Probably currency, but which?

It means Rappen. Centimes in French.
1 Franc = 100 centimes (as the word means 1/100th).

"Cmes" for "Centimes"
1 Franc = 100 Centimes (in French speaking parts of Switzerland)