Broadly speaking there are two types of blogging service, one that is hosted and managed by someone else, so any updates to the software are performed by the company offering the service.
The other type is where you are responsible for any updates to the software, but you are also likely to have a little more control over what you can do and any extra features you want to plug into your blog.
An example of a hosted service is that offered by Blogger and publishing your first article is a very simple, step-by-step process so you could easily be up and running within a few minutes.
And the real bonus about Blogger is that it is free, so you can get a taster and see if blogging is something that appeals.
The service I use for my own sites is that offered by TypePad, although there is a fee involved even the most expensive option is around £75 a month, and because I don't have to worry about updating the software I can concentrate on writing articles and still have the chance to include a number of different options.
Another popular option available to you is WordPress, which is very popular and enables you to have a hosted blog like those above, but also lets you install the software on your own server and provides a great deal of freedom to install different designs - but you are responsible for performing any software updates, these can often be security issues so are important.
A couple of other options that you may want to consider, especially if you are looking to just keep friends and family in touch with your French life, are online journals such as Vox or so called tumblelogs, which are like scrapbooks featuring short paragraphs, wesbites and photos, the most popular is Tumblr.
Don't rush into using a particular blogging platform until you are really happy with it, ultimately you want to spending time writing articles, uploading photographs and you never know video guides of your local area - not struggling to get your head round obscure bits of HTML or code.
I would suggest that the blog has a similar name to the site, maybe with the addition of "news" or "online", and then it can draw its look and feel from your main site, just make sure there are clear links between the two.
But don't turn your blog into a marketing vehicle and talk about how great you are, forever putting in front of readers endless sales talk, people will quickly turn off and not bother either reading you or telling their friends about your articles.
Providing helpful advice, useful information and simple tips is the best way to ensure others link to you and so gain an audience.
In conclusion, your choice of blogging platform will very much depend upon how "techie" you are, those, like me, who can't get their heads round creating databases, php and FTP transfers might be best going for the hosted option, others may enjoy working with a package like WordPress and testing it to its limits.
Ultimately the only way to find out is to have a go, so start writing a few posts, upload some of your photographs and start reading other blogs within your field.
Any questions? Just drop a line or two in the comments below.