His Germany visit, which he described as a "new chapter" in bilateral relations, will begin with a meeting with Chancellor Angela Merkel at her country retreat of Schloss Meseberg.
Modi also made a call for European Union unity and said India would play a positive role in enhancing that through Germany.
The pacts were signed by Finance Minister P Chidambaram and German Development Minister Gerd Mller.
The tour is aimed at boosting India's economic engagement with these nations and inviting more investment.
The two leaders enjoyed the sunshine with a walk in the grounds of Schloss Meseberg, an 18th century Baroque castle in the Brandenburg district of Germany.