French Guinea has EU license plates (upper right corner), pointing it out so you or anyone else can compare it with the mercosur ones.

Brazil, Argentina, Uruguay and Paraguay are adopting a format based on the European one and the German number plate font?

Yes, but they always use the narrow type instead of the regular, as their licence plates are less wide. In Germany, the narrow type is only a fallback if there are too many digits on the plate for the use of the regular type.

In October 2014 the members of the Mercosur South American trade bloc agreed to introduce a common design for license plates. They adopted a size of 400 millimetres (16 in) x 130 millimetres (5.1 in) similar to that used in Australia and China. The design uses the narrow script Engschrift FE-Schrift (fälschungs-erschwerdend, forgery-impeding typeface) design to show the registration code with 7 elements. The FE-Schrift was found to perform better against alteration and falsification in comparison to the Brazilian Mandatory script as shown in a test at the INTI. The design also includes a blue strip above the registration code with the Mercosur emblem in the left upper corner, the national flag of the member state in the right upper corner, and the country name printed in the center. It was agreed to introduce the Mercosur design by 2016. The actual introduction was delayed until 2018.

https://en.wikipedia.org/wiki/FE-Schrift