This is a follow up to my previous post here and following an email query from someone who stumbled across my site.
First of all, I'm so glad somebody was able to come across my story!! :D and hopefully saw some hope within. To answer their question publicly......
YOU CAN CHANGE FROM FRENCH WORKING HOLIDAY VISA TO WORKING VISA WITHOUT LEAVING THE COUNTRY AND WITHOUT COE!
A close friend of mine was able to do so actually. His company gave him the necessary papers (I guess 'change in status of residency' papers?) and he submitted his application form at the immigration office in Shinagawa. 10 days later, they contacted him to let him know that he could come change to his working holiday visa immediately.
However, I can't promise that this would be the case for everyone! In fact, I should still imagine that the COE still holds some weight. I can only assume that it is a much stronger guarantee that your paperwork will go through for the visa.
I hope that all the help and information I have presented so far was useful for some of you out there. I'm not sure how much more I can tell you about all this but if you ever want to ask me any questions, please feel free to email me about it. You can find my address on the right hand side of this page (^_^)b