A feature that might be useful in your templates lets you attach the estate’s ID to a link to another page. This means that when someone visits an estate detail page, you can generate a link to a contact form on another page, but the email from the contact form will still contain the estate that the visitor just looked.
To achieve this, you need the URL path (just the part after the domain). If your contact form is at “wpplugindoc.onoffice.de/imprint/contact” then the shortcode would be: [oo_link contexts='estate' path='imprint/contact']