Michael Henke

This plugin provides flattr-buttons for comments on your blog if the comment author entered his Flattr-ID. 
There will be an additional input field right below the comment text box. Alternativly you can input a piece of code in your theme to place the field somewhere more nicely.

Flattr Comments

This plugin provides flattr-buttons for comments on your blog if the comment author entered a Flattr-ID.

eewee

Use the system “flattr” your worpdress website.
Shortcode for :
<ul>
<li>Add Widget flittr</li>
<li>Add big button with counter (coming soon)</li>
<li>Add small button with counter (coming soon)</li>
<li>Add static button (coming soon)</li>
<li>Add Code QR (coming soon)</li>
</ul>
More informations <a href="https://flattr.com" rel="nofollow ugc">flattr</a>
PS: question, <a href="http://www.eewee.fr" rel="nofollow ugc">eewee.fr</a>.
<ul>
<li>See the <a href="https://wordpress.org/extend/plugins/eewee-flittr/changelog/" rel="ugc">Changelog</a> for what’s new.</li>
</ul>

eewee flattr

Use the system "flattr" wordrpess on your site.

Flattr Comments vs eewee flattr