Behat: Error message "you need to quote the scalar"

[paddelboot]

Trying to configure my suites and contexts as described here (http://behat.org/en/latest/user_guide/configuration/suites.html), I get the following error in my terminal:

The reserved indicator "%" cannot start a plain scalar; you need to quote the scalar at line 7 (near "paths: [ %paths.base%/features ]").

How do I "quote the scalar", since using actual quotes on the variable placeholder produces the same error?

Thanks.

[paddelboot]

I had to quote like this in my behat.yaml file:

'%paths.base%/features'.

It would be helpful to update the documentation. Tags also need quoting: '@tag'.

[stof]

The doc source is available at https://github.com/Behat/docs