If your apache version is 2.4 then you have to edit apache configuration in /etc/apache2/apache2.conf. Find

<Directory /var/www/>

and change the block like this :

<Directory /var/www/>
    Options Indexes FollowSymLinks
    AllowOverride All
    Require all granted
</Directory>

After that, restart apache.

service apache2 reload

source : https://askubuntu.com/questions/421233/enabling-htaccess-file-to-rewrite-path-not-working