[falko]

Try

location /demo/concrete5 {
root /var/www/clients/client0/web2/web/demo/concrete5;
index index.html index.htm index.php;
if (!-f $request_filename){
set $rule_0 1$rule_0;
}
if (!-d $request_filename){
set $rule_0 2$rule_0;
}
if ($rule_0 = "21"){
rewrite ^/(.*)$ /demo/concrete5/index.php/$1 last;
}

location ~ \.php($|/) {
try_files $uri =404;
set $script $uri;
set $path_info "";
if ($uri ~ "^(.+\.php)(/.+)") {
set $script $1;
set $path_info $2;
}
fastcgi_pass unixhp5-fpm-sock;
fastcgi_index index.php;
include /etc/nginx/fastcgi_params;
fastcgi_param URI $uri;
fastcgi_param PATH_INFO $path_info;
fastcgi_param SCRIPT_NAME $script;
fastcgi_param SCRIPT_FILENAME $document_root$script;
}
}