DORTMUNDtourismus is the central agency in Dortmund that takes care of touristic travels. They can help you with:

• Arranging hotel rooms in Dortmund
• Arranging touristic tours in Dortmund and the nearby region

You can contact them at wro@dortmund-tourismus.de if you need assistance planning your trip to and in Dortmund.
You can visit the website of DORTMUNDtourismus as well:
https://visit.dortmund.de/en/