Error “file_exists (): open_basedir restriction in effect” although the folder is registered?

Debian + Nginx + PHP-fpm.

Greetings. such config in nginx:

fastcgi_param PHP_ADMIN_VALUE "open_basedir=/tmp:/var/www/site:/var/www/content"; 

But on the site:

 Warning: file_exists(): open_basedir restriction in effect. File(/var/www/content/bla-bla/bla.php) is not within the allowed path(s): (/tmp:/var/www/site:/var/www/content) 

Although the access to the file seems to be obtained anyway, for nothing has fallen.