DIN, the German standard body has a working group as a subcommittee that deals specifically with the translation between OOXML and ODF.
The aim of the “Working Group Translation 29500 - 26300" is to
Identify in detail the differences between ODF and Open XML that can help harmonization and interoperability
Development of a technical report (DIN) concerning translation of ODF /Open XML in both directions.
The draft report which is in an early stage can be found here:
Link DIN NIA
The draft of DIN was also referenced by the ECMA dispositions of comments for the Open XML BRM in an emphatic way. Cmp. e.g. the standard text of response 31, 44