John Baker was a private in the Royal Pioneer Corps when he took part in the operation that led to the routing of the Nazis from occupied France.
Mr Baker, from Gosport, Hampshire, who has lost his sight from age-related macular degeneration, is appealing to be reunited with his Legion D’Honneur medal - the highest award handed out by the French Government.
The veteran misplaced the medal while attending the memorial event held by Blind Veterans UK on-board HMS Belfast on the River Thames in London on June 6.
Mr Baker said: "It was such a lovely day to visit HMS Belfast for the anniversary of D-Day but unfortunately for me it had a very unhappy ending."
He added: "I was so proud to receive the Legion d’Honneur because I wasn’t just accepting it for me but for all those who didn’t make it back or weren’t alive to get their own.
"I’m due to visit the war graves in France next week and I would be so proud to wear that medal again there.
"I really hope someone has found it and it can be returned."
Major General (Rtd) Nick Caplin, chief executive of Blind Veterans UK, said: "John is a lovely man and has rightly been awarded the Legion d’Honneur for his part in the liberation of France.
"As soon as we heard that the medal had gone missing we returned to the ship to search for it but, unfortunately, it wasn’t found.
"There were thousands of people around HMS Belfast on Thursday so hopefully someone knows something or has even handed it in somewhere."
He added: "We hope that John’s treasured medal can be found but we will ensure that a replacement medal is presented if not.
"If anyone does have any information all of our contact details are on blindveterans.org.uk."
Mr Baker joined the General Service Corps in September 1942 and three months later transferred to the Hampshire Regiment.
In May 1943, he transferred to the Royal Pioneer Corps and landed in Normandy on D-Day.
A Blind Veterans UK spokesman said: "He helped to build a bridge across the Rhine during the advance into Germany and was then transferred back to the Hampshire Regiment in March 1947, serving in Austria.
"He then returned to Reading before going to Eritrea. Discharged in March 1950, he joined the Merchant Navy. He then became a school caretaker in Gosport, retiring at 64.
"John lost his sight due to age-related macular degeneration and has been supported by Blind Veterans UK since 2009."