The Testing of Robotman (1951). Writer: Joe Samachson? Art: Joe Certa. Robotman tries to join the Cluesters, a club of the world's greatest detectives, and has to solve a mystery challenge as an initiation test.
I do not know the author here, but the story has features one associates with John Broome. The group of detectives in this story resemble those in the final
Justice Society tale, John Broome's "The Mystery of the Vanishing Detectives" (All Star Comics #57, February-March 1951). They are the sort of
"great sleuths" familiar to people from mystery novels and movie whodunits. They are from countries around the world, just as in the movies, and both
stories include a Chinese sleuth, who is treated in a respectful manner. This is a notable early occurrence in the comics of positive Asian characters. He
behaves in a manner of complete equality with the other great detectives from France and England. Broome would be a pioneer in integrating non-white characters
into the comics.
Secret of the Phantom Bells (1958). Writer: John Broome. Art: Sid Greene. Charlie Chan searches for an ancient Roman treasure hidden in an old English castle.
Broome also includes a good subplot about three sleuths from three countries who also come to the village to solve the mystery. This international group
recalls the four great detectives in the final Justice Society tale, Broome's "The Mystery of the Vanishing Detectives" (All Star Comics #57,
February-March 1951). One of the sleuths in that earlier story was a thinly disguised version of Charlie Chan, by the way. Broome takes this subplot in
different directions here than in the earlier story.
The DC Universe has also been home to a Charlie Chan knock-off, Harry Wan, who appeared in All Star Comics #57 in 1951. That story featured him alongside analogues of Maigret, Sherlock Holmes, and a Turkish policeman I cannot name an analog for.
Synopsis: Batman and Robin are invited to attend a meeting of great detectives. The Guest of Honor, Dana Drye, is shot to begin the meeting. The other detectives and Batman join together to solve the mystery of his murder. Batman follows several leads. Eventually he learns that Drye was dying of an incurable disease, and his death was suicide. Drye had also discovered Batman's secret identity. In order to protect his own secret, Batman pretends to fail in his effort to solve the case.
Impossible Man Special: the Impossible Man's children imitate various fictional sleuths after seeing a marathon of such films at a theater. They imitated, as I recall, Sam Spade, Charlie Chan, and perhaps some others. (They also imitated Daredevil and Moon Knight.)
The Case of the Baker Street Bionics, episode of the Bionic Six
http://dc.wikia.com/wiki/DC_Comics_Presents_Vol_1_68 Only notable as two
people get bored and start making list of sleuth franchises they have watched, e.g. Mr. Moto, Charlie Chan, the Saint, etc.