The partnership will see the two agencies working together to benefit shared clients, as well as pooling highly complementary knowledge and expertise when pitching together for pan-European and global clients.
With both agencies strong in retail and fashion, Seven also has extensive expertise in food, financial services and B2B, while Burda Creative (part of the €2bn Burda publishing empire) excels in automotive, pharma and technology.
The two agencies have combined billings of €50m.
Seven CEO Sean King said: "International expansion is an important part of our growth strategy and Burda share our view that multi-channel, editorial content is how global businesses can most effectively deliver their brand promises.
"Burda are strong where we'd like to be, and Seven's expertise complements theirs too. So we are formalising our sharing of knowledge and innovation to ensure our clients benefit from new ideas, different perspectives and international economies of scale.
Burda Creative CEO Gregor Vogelsang said: "As more clients seek brand consistency delivered through content marketing on a global scale, seeing our multi-channel editorial approach mirrored by Seven, it was an easy decision for us all to become partners. We are both actively looking for agencies in other markets who share our collective ambition and approach."