There is another Eurostar FIP promotion from 21st February until 9th April 2006.
Fares are as follows:
First Class:
Paris, Marne, Lille, Brussels: £25 single, £50 return.
Second Class:
Paris, Marne: £12 single, £24 return.
Lille, Brussels: £10 single, £20 return.
Availability is limited