Reuters reports that up to 230 staff from police, environmental and public prosecution departments were involved in the investigation in Benz's home town of Stuttgart and ten other sites across Germany.
The team was specifically searching for potential cases of fraud in advertising material, stating false exhaust emissions on certain models.
Documents that hinted at the existence of a 'defeat device' - similar to that used by Volkswagen in the now-infamous 'Dieselgate' scandal - were also sought.
Daimler reportedly said it was cooperating with the authorities, but did not comment on specifics of the case.
But while investigators said they were targeting "known and unknown employees at Daimler", an unnamed source for the carmaker later told Reuters that they believed board members were not being targeted.
Daimler is not the only carmaker currently under the eye of authorities in Germany, with Fiat Chrysler also under investigation last month.
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