The EU banned list prohibits listed airlines from flying within European airspace. It does not expressly address issues such as ticketing. Presumably this means that a European based travel agent is free to issue tickets for a banned airline as long as it does not fly within European airspace. I also presume that this also means that they are under no obligation to inform you of this status either (though they may be partially liable for death or serious injury caused as a direct consequence)
Transport: List of airlines banned within the EU - European commission
Anansis