Tag menu and duplictate content

[gilplane]

Good morning everyone,
1 / I use the tag menu on a 3.8.3 joomla website with the sef plug in activated and have problem of duplicate content.
Is it a bug with this menu tag fonction?
For exemple on this blog https://www.ovalp.com/fr/vallouise Google find also the same page on this url https://www.ovalp.com/fr/vallouise/prov ... ote-d-azur witch is not an url coming from one of my menu .
Also on Google result for "blog vallouise" many other url do duplicate content (https://www.google.fr/search?q=blog+val ... gAbO_7H4BQ)
2 /And another problem with this menu tag I can't find how to choose the number of article appears before it generate an another page (actualy after 20 articles) and give this kind of situation https://www.ovalp.com/fr/hautes-alpes?start=20 ?

If you have and idea how to solve nativly with joomla without any extension, this two problems, thanks in advance.
Best Regards

[luisalves]

I have any question?
You use extension to build this website? I think your site isn't sick!
Some extension:
https://extensions.joomla.org/extension/maxi-menu-ck/
https://extensions.joomla.org/extension/dj-menu/
1. Build new menu with:https://www.evohosting.co.uk/blog/web-d ... xtensions/
2. Fix all duplicate content and Fetch as Google
You should use 301 Redirecting duplicate content!
Added this to .htaccess
RewriteRule ^m/(.*)$ /$1 [L,R=301]
Learn more: viewtopic.php?f=712&t=950341
viewtopic.php?f=712&t=956106

[gilplane]

Hello,
Thanks Luisalves for your answer.
I try to use the less of extension because of update and security reason, also for durability over time of the website (Joomla will always stay alive but the extensions?).
I am afraid that those duplicates content came from the moment the option of delete the ide from the url arrived. It doesn't seem that it's normal that url's not on the menus appears...Do you think it's a Joomla native bug ?
Thanks

[gilplane]

Thanks Pitercheck for your response.
Yes robots.txt and/or webmastertools (google search console) but there are many urls. Hope this will be solve in a next version because on my side it seem that Joomla 3.8.3 generate many, many duplicate content...
And the SEF plug in give all thoses duplicates contents urls as canonical !!
Google doens't seem so bad, at this time, for the moment, about that..Do they have this (Joomla Seo Bug?) in there algorythm?
Thanks for your help and infos.
Best R