Police stormed 54 houses and businesses, as well as Islamic places of worship, resulting in the arrest of a Tunisian Isis recruiter.
The state of Hesse was swarming with officers in the early hours of the morning as police targeted extremists in the country.
The operation was combating “serious state-threatening violence” officials revealed after a 26-year-old Tunisian people smuggler for ISIS was arrested.
It is currently believed the man arrested was involved in the attack on the Bardo Museum in Tunisia in March 2015, which left 20 tourists dead and other ISIS attacks.
“According to evidence gathered so far, attack plans were still in an early phase and had not selected a specific target,” said a spokesperson for the Hesse state criminal investigation office.
Officers later revealed the Tunisian arrested has been wanted since August 2015 and is a known ISIS recruiter.
Police believe the man was gathering a group to commit a terror atatck on German soil.
Although he has not been named police revealed he had been in Germany for ten years until 2013.
He then returned during the refugee crisis of 2015 posing as an asylum seeker.
The alleged jihadi was arrested after his arrival in Chancerllo Angela Merkel’s nation over a previous conviction for bodily harm in 2008.
He spent 43 days in prison after which Tunisian authorities called for his return.
But authorities claimed Tunisia had not submitted the required extradition documents so he had to be released.
The same delays meant the Isis supporter who carried out the Berlin Christmas market attack could not be deported leading to Angela Merkel promising reforms.
Police said the Tunisian has been under round the clock surveillance but was not taken into custody to avoid jeopardising the ongoing investigation, Frankfurt police said.
On Tuesday night prosecutors in Berlin said that they arrested three people suspected of preparing to travel to the middle east for ISIS training.
The trio were associated with the Fussilet mosque in Berlin, known as a gathering point for radicals, prosecutors said.
Anis Amri, the Berlin Christmas market attacker, visited the mosque shortly before he ploughed a lorry into crowds on 19 December, killing 12 people.