I have never seen `1,23 €` really, in dutch the euro curreny sign comes before the number. Also there are no official European rules on this. Same with EUR, can be both before of after, but most common use is before in NL, while dutch speaking part of belgium often places the currency code behind the number.
At least that is how the dutch language institute states it.

Here is more info:
http://en.wikipedia.org/wiki/ISO_4217#Position_of_ISO_4217_code_in_amounts
http://publications.europa.eu/code/en/en-370303.htm