Redirection loop URL rewriting - mod-rewrite

Question

I'm redirecting all my .php extensions to .html, but I'm getting a loop problem.
For example, from:
-mywebsite.com/country/france-php/paris.php
to
-mywebsite.com/country/france-php/paris.html
Here is my .htaccess:
RewriteEngine On
RewriteBase /
RewriteRule (.+)\.php$ $1.html [R=301,L]
RewriteRule (.+)\.html$ $1.php [L]
FallbackResource /index.php
When analyzing with redirection detective I get many redirections to:
-mywebsite.com/country/france-php/paris.html

Answer 1

Do the first redirection based on raw request received:
RewriteCond %{THE_REQUEST} ^GET\ /(.+)\.php
RewriteRule ^ /%1.html [R=301,L]
RewriteRule ^(.+)\.html$ /$1.php [L]
To load index.php as index.html too, you can add the following rewrite at the top:
RewriteCond %{REQUEST_FILENAME} -d
RewriteCond %{REQUEST_URI} ^(.*)/$
RewriteRule ^ %1/index.php [R=301,L]

Answer 2

You can try your rules this way.
RewriteEngine On
RewriteBase /
RewriteCond %{THE_REQUEST} ^[A-Z]{3,}\ /(.+)\.php
RewriteRule ^ %1.html? [R=301,L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule (.+)\.html$ $1.php [L]

Answer 3

Try:
RewriteEngine On
RewriteBase /
RewriteCond %{THE_REQUEST} \ /+([^\?\ ]+)\.php([^\?\ ]*)
RewriteRule ^ %1.html%2 [L,R=301]
RewriteCond %{DOUMENT_ROOT}/$1.php -f
RewriteRUle ^(.+)\.html(?:(/.*)|)$ $1.php$2 [L]
The problem is that the rewrite engine loops and your two rules keep overwriting each other. By adding some conditions, you can prevent that.