Buy one entrance ticket (at full price) and get the second free at the Lille Palace of Fine Arts:
Lille Europe and Lille Flanders are two separate, but neighbouring train stations: they are only 450 metres apart.
The easiest way to get from one station to the other is therefore on foot (it's a 10-minute walk), even if you have luggage with you: the older Lille Flanders train station is set on the ground level, while the new Lille Europe train station has lifts and escalators at each entrance.
Whether you walk via Place François Mitterrand (the promenade between the Euralille shopping centre and Lille Europe train station) or the Le Corbusier Viaduct, the raised platforms and dropped curbs mean that you won't have to navigate any obstacles with your buggies and wheeled suitcases.
In both stations, signs clearly indicate the route to the other station. Of course, you can also ask station staff. Or simpler still, you can follow the flood of regular travellers making the journey. Their large number (and their luggage) make them easy to spot!
The UK authorities require all passengers travelling on Eurostar trains to London to be checked in and go through passport control. These procedures also apply to passengers travelling to Lille or Calais, even though they will remain within the Schengen Area.
This means that anyone travelling to Lille or Calais must also check in before boarding at Brussels (Midi/Zuid) at least 30 minutes before their departure time. However, passengers for Lille and Calais check in via a dedicated Intra-Schengen terminal located on the first floor of Brussels (Midi/Zuid) station (balcony over the Galerie du Midi, Place Horta side).
From this terminal, passengers can go directly to carriage 16 or 18 (depending on train type), which only accommodates those travelling to Lille and Calais.
This check-in procedure does not apply to passengers travelling to Lille on Thalys or TGV® Brussels-France services. These travellers may go straight to the platform.
For commuters travelling daily between Brussels and Lille, there is a season ticket valid on all TGV Brussels-France and Eurostar trains operating on this short route.
This season ticket is made up of three items:
1. A "mother" card
The mother card costs €5 and is valid for five years on the Brussels-Lille route (in 1st or 2nd class), as well as on any connecting train taken within metropolitan Brussels.
2. A monthly validation ticket
The mother card is only valid when accompanied by a monthly validation ticket. This validation card is valid for a period of one month, starting from your chosen date. It can be purchased maximum 31 days before the validity period begins.
3. A seat reservation for every journey
In addition to your season ticket, you must book every journey. The cost of this is €3 per journey.
The three items of this season ticket are sold exclusively at SNCB International "immediate departure" ticket offices at Brussels (Midi/Zuid) station.