Abendanon has won the European Player of the Year award, the third time a French-based English player has won it.
Yet since the 2011 Rugby World Cup, an RFU rule has said only those involved in domestic rugby can play for England.
"Having that rule in place restricts players from playing at the top level," said 28-year-old Abendanon.
"You're playing with the best players in the world and coming here has made me a better player and better person.
"I know exactly why the RFU has that policy in place and I don't expect it to change - but I have changed my mind on it since moving out here."
Abendanon played two matches for England in 2007 but last summer he moved from Bath to Clermont, scoring a fine solo try in the 24-18 loss to Toulon. in the final of the European Rugby Champions Cup.
Toulon's Steffon Armitage and Jonny Wilkinson, now retired, won the European Player of the Year award, in 2014 and 2013 respectively.
After winning the award, Abendanon told BBC Radio 5 live he "would encourage more people to move" to France.
Abendanon has said "it would be a dream come true" to represent England in the 2015 World Cup, but England head coach Stuart Lancaster has only picked domestic-based players.
"I played for 10 years in England and came out to France because I thought my international career was over," added Abendanon. "I'm sure Steffon felt the same.
"Playing in France has rejuvenated our games and whether we get rewarded for that is up to Stuart."
Listen to Abendanon speak to BBC Radio 5 live
Clermont full-back Nick Abendanon says the Rugby Football Union should allow players working for clubs outside England to represent the national team.