At fist you have to install new plugin "Tree Style Tab". But current version doesn't suport hiden sidebar with tabs. It is needed modifle Firefox in profile:

cat ~/.mozilla/firefox/profiles.ini
cd ~/.mozilla/firefox/<profile>/ && mkdir chrome

Create new file userChrome.css in created folder "chrome" with following content:

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");

/* to hide the native tabs */
#TabsToolbar {
    visibility: collapse;
}

/* to hide the sidebar header */
#sidebar-header {
    visibility: collapse;
}