Summary of the general rules:
® means “Registered Trademark” (as validated by the Patent & Trademark Office).
™ means “Trademark” (any mark filed with a Trademark Office).
© means “Copyright”.
As should first be recalled, the © (copyright) is a reserved right notice concerning any work that can be copyrighted. This symbol is generally followed by the name of the copyright holder, and the year of first publication. The aim is to inform any third parties and to deter potential infringers.
There is also another, more recent symbol – the copyleft 
– which symbolizes the authorization given by the author of a piece of copyrighted work (work of art; text; other…) to use, study, modify or disseminate his/her work, insofar as such authorization remains protected (any creations generated from copylefted elements are systematically protected by this copyleft).
Regarding the ®, there is no obligation in France to use the ® or ™ types of symbol with your trademark to assert and secure your trademark rights. The Paris Convention of 20 March 1883 even provides expressly in its article 5 that “The recognition of rights does not require that any sign or statement of a patent, utility model, registration of a trademark, or filing of an industrial drawing be mentioned or affixed on the respective product”.
You do not have to systematically use the ® symbol to have your trademark right recognized.
However, in certain countries, including the United-States, the use of the ® symbol is a prerequisite for obtaining damages, or is even sometimes essential in order for the trademark holder to be able to file an infringement action.
In France, the ® symbol does not have to be used systematically, but it offers two major advantages, as it both prevents infringement and deters potential infringers.
Our recommendations:
– It is advisable to affix this registration symbol onto any medium that reproduces the registered trademark (particularly if your trademark is meant to be exported to the US and you don’t want to be limited in terms of the actions you may wish to take there). However, you should be careful with the risk of deception of third parties, as long as the trademark has not been registered. The registration sign (®) can only be used in countries where the trademark has effectively been registered with the Patent & Trademark Office (i.e. in the meantime, when the trademark has simply been filed to allow the owner to use the TM symbol).
– It is important to include this new visual element in your graphic charter any time you use the trademark concerned, whether it is a word mark or a graphic mark. You may even include and write this requirement in your trademark policy – in particular for all that regards the use of your trademark by licensees, subsidiaries and distributors (for more information on the relevance of writing a trademark policy, go to http://www.pi-xoo.com/2014/01/10/563/).
Certain companies, like Jean-Louis David, do not simply attach the ® or ™ symbols to their trademark, but also incorporate them into their graphic charter: 
There is no particular requirement as to the precise positioning of the symbol, so that a trademark like 
(in which the position that is generally reserved for the said symbol is already occupied by an asterisk) could even position the © in the dot on the “i”.
These ® or ™ symbols are short (so that they won’t alter the mark), but certain companies prefer to go further: 
– and either give the information a pro-eminent position: this is the art of proactively transforming a legal obligation into an asset! And as IP professionals, we can only support this communication approach, as filing a trademark is not only an expenditure, but also a protection, and first of all a true asset! A value!
– or file a trademark: on 27 June 2013, the Community court gave a judgment on an appeal (see http://curia.europa.eu/juris/document/document.jsf?text=&docid=138921&pageIndex=0&doclang=FR&mode=lst&dir=&occ=first&part=1&cid=145557) , following an opposition based on 
the mark against the filing of 
. When appraising the disputed decision, the Board of appeal considered that the sign was “clearly used as a mark by the claimant, and not as the ® symbol, as testified by the size of the mark in question and the obvious graphic differences between the two signs”. The board stated that the marks were too similar, and finally rejected the filing.
This decision has shown, in particular, that there can actually be marks that simply consist of this symbol! Which means that care should be taken, when using this symbol, not to tend to use it as a trademark (by adjusting the size or adding graphic features), in which case it would be necessary to make sure that no registered trademark owners in your field of activity may wish to challenge such use of the symbol.
You must attach the ® symbol to your registered trademarks, and you can even incorporate it into your graphic charter in a stylish fashion, but you should ask your IP counsel whether such use can be considered as using the symbol as a trademark. And if the risk does exist, you should be fully aware of it and make all prior checks required.