I found an answer myself:
Redirecting without a condition
When you use the Wordpress plugin “Contact Form 7” you can redirect the user to another page after submitting the answers by the follwing code:
on_sent_ok: "location.replace('http://www.redirectedpage.com');"
The line of code you have to copy into the “settings” box at the end of a specific form you created.
Redirecting on a condition
If you want to make the redirecting depending on a specific answer, you can use the following code:
on_sent_ok: " if (document.getElementById('car').value=='yes') {location.replace('http://www.redirectedpage1.com')} else { location.replace('http://www.redirectedpage2.com/') } "
The code in bold letters has to be changed by your settings.
For example: The question with the id “car” has two possible answers: “Yes” or “No”. If a person selects “Yes” he or she should be redirected to “http://www.redirectedpage1.com”. If “No” is selected, the user should be redirected to “http://www.redirectedpage2.com/”.