There are many factors that figure into this equation. Amongst them are the duration of the event, the interpreting mode and the topic or nature of the event. These factors vary significantly in different contexts.
The standard daily rate for simultaneous interpreting ranges from 800 to 1000 €. This rate includes not only the time spent on site, but also the thorough preparation of the event based on materials provided by you and my own research.
The actual rate depends on the duration, mode and content of the event.
Since these factors can vary signifcantly, how about you just contact me? This way, you will get a better idea of the rate I can offer you.