An estimated 20,000 members of the Green Army are expected to march on Paris for the vital World Cup play-off against France on November 18.

When the countries last met in Paris in October 2004, more than 20,000 Irish fans flooded into the Stade de France for the 2006 World Cup qualifier. But legend has it the figure was closer to 40,000.

The green hordes then made themselves heard by out-singing the home support.

Similar numbers are expected to make the trek again but just how many make it into the stadium will depend on the take-up from French supporters.

Around 10pc of ticket allocation goes to the away fans. Based on the Paris stadium's capacity of about 80,000, that would give Ireland an allocation of around 8,000 tickets.

But depending on the interest in the game among French supporters, many more tickets could become available closer to kick-off.

Irish expats living in France are also likely to pick up a fair number of tickets.

Fans can apply to the FAI for tickets by emailing their names, addresses and contact information to ticket.office@fai.ie.

It is customary to give preference to fans who regularly attended away games. Once that number has been whittled down, block bookers are then considered.