The 37-times capped Millar, who will stand down as IRB chairman in December, said that he accepted the decoration on behalf of all the 2007 World Cup staff.
"It is a huge honour to be given such a prestigious award and it is very much appreciated. However, I feel that I am accepting the Legion dâ00Honneur on behalf of all of the IRB and Rugby World Cup personnel who worked tirelessly to ensure the delivery of the 2007 World Cup in France," he said.
"It was a memorable and ultimately successful tournament that will be remembered as the most successful in the Rugby World Cup's 20-year history.
â00We value our traditions and history in rugby that are based on fair play, loyalty and friendship. Such characteristics came to the fore during the tournament and I would like to publicly thank the people of France for their tremendous support of the tournament.
"They volunteered by the thousands and turned up in their millions at the stadiums. The France 2007 organising committee were exceptional in their delivery of key programmes and I would also personally like to thank them for all of their hard work over the past four years,â0 added the 73-year-old, who was coach of the 1974 British & Irish Lions as well as manager of the 1980 Lions.
IRB chief executive officer Mike Miller was quick to praise the significant contribution that Millar has made in his capacity of IRB chairman to the advancement of the game and Rugby World Cup.
â00While Syd rightly praises the hard work of the IRB and RWCL teams, without his vision and leadership the huge advances made in rugby in the last five years would not have been possible.
â00He personally ensured the modernisation of the IRB governance structure and the creation and delivery of the unprecedented US$50 million strategic initiatives which laid the foundations for the most competitive Rugby World Cup to date,â0 said Miller.
A formal acceptance ceremony will be arranged for Millar's family, friends and colleagues from rugby in his home town of Ballymena.
Millar, who played for Ireland between 1958 and 1970, will be remembered as one of the game's great administrators. He represented Ireland as a player, coach and manager, and was elected President of the Irish Rugby Football Union in 1995 after 10 years of service.
He served on the Six Nations Committee and was also chairman of the British & Irish Lions from 1999 to 2002. Millar joined the IRB Council as an Irish delegate in 1994 and served in that position until taking over the role of interim chairman after the death of Vernon Pugh QC in 2002.
Elected IRB chairman in November 2003, Millar presided over the modernisation of the IRB, including a new governance structure and the implementation of the existing strategic plan