Have others noticed that French people haven't yet "decided" how to fit the word euro into their language, with its system of phonetic liaisons? The currency itself seems to be unanimously accepted, even though I get the impression that people in France are still slightly are in the dark when it comes to understanding how much money a sum like 8,457 euros represents "in real money" — French francs, now obsolete.
What do I mean by "phonetic liaisons"? There are great differences between English and French when it comes to pronunciation, as we all know. In English, we pronounce words fairly separately. We do have some contractions (don't, won't can't, I'll, etc). French has contractions too. But French is not actually pronounced as separate words.
A string of spoken French is a string of syllables, and word boundaries are not respected. In addition, there are a lot of words, especially the plural forms of articles and adjectives, where the final letter of the word is not pronounced (les, des, ses, mes, chers, bons, grands, par exemple). Not pronounced, that is, UNLESS they are followed by a noun beginning with a vowel, like amis ("friends").
You don't pronounce the phrase mes amis as two discrete words. You pronounce it as three syllables, and the last consonant of mes becomes part of the second syllable, whose vowel is the initial vowel of amis. The result is something like [may-zah-MEE] — three syllables. Why do I put MEE in all caps? Because the last syllable of a phrase is always stressed in French. Note that the final S of amis is not pronounced here.
Euro is a word formed on the same model as ami. When it comes to its pronunciation, however, the situation is less than regular and stable. Watching a nationally popular TV show just now, I heard one of the panel members talk about paying troi' euros for a rose chez les fleuristes. If it had been trois amis, the person would have said [trwah-za-MEE], pronouncing the S of trois, and not [trwah-a-MEE] without the Z sound.
At the supermarket, the cashiers frequently quote prices of deu' euros or troi' euros. Around Saint-Aignan, I often hear people say vin' euros for 20€ or, worse, vingt-z-euros. As far as I know, the correct pronunciation is vingt-t-euros, sounding the final T of the word vingt. There is no final S on the word for 20 (vingt).
The correct pronunciation of 2€ is deux-z-euros. Trois euros should, by all rights, be pronounced trois-z-euros. And I think people have "agreed" unanimously that un euro is pronounced un-n-euro, with liaison of the final N of the number un.
People also seem to be pretty consistent in saying cinq-k-euros (5€) which is correct. Even six-z-euros (6€) seems to be catching on. The same is true for 10€, dix-z-euros.
After 20€, the most blatant cases of flottement concern the number 100. According to the established rules of French pronunciation, 100€ should be pronounced cent-t-euros. All too often, I hear cen' euros, where the T of cent is not pronounced. But I don't think I've actually heard 100€ pronounced as cent-z-euros, which would be both jarring (on the same level as vingt-z-euros) and confusing, since "cent-z-euros" could be heard as "sans euros" -- without euros. In the singular there is no S on cent in French.
Deux cent-z-euros would be the correct pronciation of 200€. I need to start listening more closely to see if people are actually saying deux cen' euros, leaving the final S of cents silent.
En principe, the word euro should function phonetically exactly as the word heure does. French speakers unanimously say deux-z-heures, trois-z-heures, dix-z-heures, and vingt-t-heures. Cent heures — 100 hours — is an expression you hear less often, but I think most French people would pronounce it correctly as cent-t-heures. The initial H of heure is completely silent and it's as if it doesn't exist except in writing; the word effectively starts with a vowel sound. The same pattern occurs with the word for year — an — deux-z-ans, trois-z-ans, vingt-t-ans, and cent-t-ans — La Guerre de Cent Ans, The 100 Years War between England and France in medieval times, is a commonly known expression in which Cent Ans is pronounced is pronounced cent-t-ans.
The word euro seems to be taking on the characteristics of those words in French that begin with an "aspirated H" -- an H that prevents liaison of the last consonant of a preceding number or adjective.
For example, there's the word haricot (bean). Or hibou (owl). Or héros. Des haricots is pronounced [day-ah-ree-KOH] -- the S of des remains silent. The same is true with des héros — [day-ay-ROH].
The word euro seems to be following that pattern, at least for a segment of the French population. The only other word I can think of that doesn't begin with an H but follows the pattern of words beginning with an "aspirated H" is the word for eleven, which is onze. In a phrase like les onze hommmes ("the eleven men"), you don't pronounce the S of les.