An IAAF ethics board found that the influential former deputy secretary general had lied to the inquiry over the funds.
An International Association of Athletics Federations ethics board found that the influential former deputy secretary general had lied to the inquiry over the funds.
Davies' wife and IAAF project manager Jane Boulter-Davies and medical manager Pierre-Yves Garnier were both allowed to resume working for the world body, with each ordered to pay 2,500 euros in costs.
But the ethics board ordered that Davies, named by Coe as his chief of staff when he took over in August 2015, was "expelled from his position with the IAAF with immediate effect" and ordered to pay 5,000 euros in costs.
Davies' downfall was "accepting a concealed remuneration" through Diack's son Papa Massata Diack, lying about it to the ethics board and failing to disclose it to French judicial authorities and the World Anti-Doping Agency (WADA).
Davies received €30,000 euros, €5,000 paid into his joint bank account with Boulter-Davies, while €25,000 went into his own account, without his wife's knowledge.
"Mr Davies has admitted misleading the investigation," said an ethics board report.
"That is an extremely serious matter. It is all the more serious for the fact that Mr Davies only admitted his lie when his hand was forced upon requests being made of him for his bank statements."
Davies, the board said, "has admitted a serious error of judgment and has reflected upon and sincerely apologised for that error".
Davies will be free to seek employment elsewhere in athletics and to be involved in IAAF organised competitions. He can also still appeal to the Court of Arbitration for Sport.
The allegations stem from an email sent by Davies to Papa Massata Diack on July 19 before the 2013 World Athletics Championships in Moscow which outlined a plan to delay naming Russian doping cheats to avoid bad publicity.
In the email to Papa Massata, a marketing consultant, Davies suggested a "very secret" five-point plan to manage media reaction to doping failures.
Lamine Diack is now under house arrest in France on corruption and money laundering charges while Papa Massata is wanted by French authorities but is in his native Senegal.
The ethics board ruling came on the same day that Coe again found himself in the spotlight amid allegations he knew of corruption claims concerning the Russian doping scandal four months before they became public.
Coe told a House of Commons committee in December 2015 he was "not aware" of specific allegations of corruption in Russian athletics until a German documentary in December 2014.
But in an August 2014 email to the IAAF ethics commission published Tuesday by the parliament culture, media and sport committee, Coe, a two-time Olympic 1500m champion, stated: "I have now been made aware of the allegations."