Final answer:
The services sector of Germany's economy boasts the highest GDP relative to the labor force due to its comprehensive range of economic activities and the modern shift towards service-based economies.
Step-by-step explanation:
The sector of Germany's economy that had the highest GDP compared to its labor force is the services sector. This sector includes a wide range of economic activities such as engineering, finance, healthcare, education, and legal and financial services. In contrast, the agriculture sector makes up a smaller part of the economy, and although the industry sector is substantial, it does not surpass the services sector in terms of GDP contribution relative to workforce size. The service sector's dominance is attributed to its encompassing nature of non-physical goods and the shift in economic structures moving away from conventional manufacturing to service-oriented transactions and professions.