Line Markert advises authorities and companies within the public and semi-public sector on the legal relations of municipalities, the special matters concerning municipal companies and questions relating to the supply of heat, water and waste water. She advises municipalities and municipal companies on the realisation of complex projects and strategic cooperation, for instance inter-municipal climate adaptation projects, development supply area. Line Markert also advises public authorities and companies on questions relating to the interface between public handling of assignments and commercial activities, including the establishment of cooperation with private companies and organisations.

Line is mentioned in the following international legal directories:
IFLR1000 - Energy & infrastructure og Project development (Rising star)
Legal 500 - Environment (Recommended Lawyer)