Australia last week, Germany soon.
Last September, Monaco completed 12 agreements to exchange tax information in order to move off the OECD's grey list of uncooperative tax havens and onto the white list [1]. Since then, agreements have been signed with 4 more countries, Argentina, Sehchelles, Netherlands, and just last week, with Australia. It's likely that Germany will bring the number up to 17 soon, as negotiations are being finalized and documents being drawn up.
An agreement with Germany is important for Monaco, since it was one of the 3 countries, with France and the USA, which took the lead in denouncing tax havens and defining new rules for transparency. In order to increase credibility for the actions taken by the Principality, further agreements are being discussed with Finland, Denmark, Sweden, Norway, Iceland, Greenland and the Faroe Islands. In addition, the OECD are monitoring the agreements and a progress report will be published in summer.
Links:
[1] http://www.monaco-iq.com/Consequences-of-being-white
[2] http://www.nicematin.com/article/societe/accord-de-fiscalite-avec-laustralie-et-lallemagne