The investigation into the 2 million Swiss franc payment from FIFA to UEFA president Platini in 2011 form part of a broader corruption scandal shaking the world football body.
The pair were provisionally banned for 90 days by FIFA on October 8, pending the full investigation by FIFA's Ethics investigators which concluded on Friday. The body could, if they deemed it suitable, impose a further ban on one or both.
Blatter also faces a Swiss criminal investigation over the matter.
“The adjudicatory chamber of the independent Ethics Committee...has today opened formal adjudicatory proceedings against Joseph S. Blatter and Michel Platini based on the final reports submitted by the investigatory chamber,” said a statement from Eckert’s spokesman.
The payment was made in 2011 for work Platini had completed nine years earlier, the Swiss attorney-general's office has said, adding Platini was considered "between a witness and an accused person".
Both men have denied wrongdoing.
Blatter is due to stand down as FIFA president after a vote to choose his successor at a special FIFA congress in Zurich on February 26.
Platini submitted his nomination papers to run in that election shortly before his suspension but his bid is on hold pending the outcome of his case.
The Frenchman has challenged his provisional ban in the Court of Arbitration for Sport (CAS) and is also expected to appeal the final verdict with the Lausanne based body, which is sport's highest tribunal.
The Ethics investigators said on Friday that they had submitted their final reports on Blatter and Platini and requested unspecified sanctions against the pair.
Blatter's lawyers issued a statement on Saturday saying he was confident of being cleared.
"President Blatter looks forward to having this matter decided impartially and based on the facts, and he is confident he will be vindicated when the facts are independently examined," said a joint statement from Blatter's Swiss lawyer Lorenz Erni and U.S. lawyer Richard Cullen.
FIFA became embroiled in the worst corruption scandal in its 111-year history in May when 14 football officials, including two FIFA vice-presidents, and sports marketing executives were indicted in the United States on corruption charges. Swiss authorities also instituted proceedings.
(Reporting By Simon Evans)
