# :anchor not working for odt export

I am trying to export images with odt export from org-mode and to change the anchor of the image (default to-paragraph) to "as-char".

I tried the following code:

 #+ATTR_ODT: :anchor "as-char"
[[./orgmode.png]]


And the obtained result in LibreOffice is:

The anchor of the image remains "to-paragraph". Is it a bug or a misunderstanding of the :anchor tag ?

Config: GNU Emacs 25.2.2, LibreOffice 6.0.3.2

Either the documentation describing the :anchor tag is wrong, or the implementation has diverged from the documentation. This works for me in org-mode version 9.1.14 if I don't specify the quotes around the :anchor tag value, ie :
 #+ATTR_ODT: :anchor as-char