To get an idea of what journalists are actually being paid, visit the ‘Rate for the Job‘ page of the NUJ’s London Freelance Branch. Note that these are UK rates however, so are often less than charged in continental Europe (lower costs).
As stated by London Freelance Branch, these rates should be considered minima; you should always begin by bidding higher. Remember that agreeing a rate for a project is a process of negotiation – the NUJ runs courses on how to become a better negotiator!
See: Rate for the job