He thanked Finland for what he said was a "very efficient" presidency of the European Union in the second half of 2006, and underlined that the adoption of the European constitution was the key issue of Germany's six-month presidency.
Peters said submitting a constitution report in June 2007 would be Germany's most difficult task because France and the Netherlands had turned down the draft constitution.
The ambassador said the issue of the constitution was in Croatia's interest as well because the Nice Treaty stipulates that "the EU needs a new institutional framework if it has more than 27 countries".
Peters said the Nice Treaty was unequivocal and that he did not think Croatia could join the Union based on it.
"Our aim is to conduct confidential talks with EU countries and the European Commission so that we can see if we have a common position," he said.
Asked if Germany intended to involve Croatia, as an accession candidate, in discussions on the constitution, Peters said he was familiar with such initiatives but that a solution had not been found yet.
"I personally think this would be useful and good, and so does my colleague in Ankara. However, all 27 countries have to agree on this."
Speaking of Croatia's accession process, he underlined that Croatia was briefly mentioned in the German EU presidency programme in one sentence, which he said was a good sign.
"Germany will encourage and support the ongoing accession process of Turkey and Croatia in keeping with the progress the two countries make in meeting their commitments," it is stated in the programme.
The ambassador said the fact that Croatia's and Turkey's entry negotiations were separated last year was positive as Croatia's negotiations would be accelerated.
"It is certainly in Germany's interest for Croatia to join the EU, but I don't know of any EU country that would not want this," Peters said, underlining that Croatia must continue with reforms, notably of the judiciary, and with fighting corruption.