The writer of this page is neither a specialist of the right nor of medicine. He thus declines any responsibility in the event of bad interpretation of a law. Consequently, this text should not be regarded as a legal reference, but only as an explanation of the bases of the medical right.
All the official texts can be consulted on the site « Légifrance ».

Medical errors
What does it hapen in the event of a medical error ? In some countries, as in the United States, the lawsuits against the surgeons multiply. In France, the L1142-1 article of the code of the public health protects a category of professionals (of which doctors, dental surgeons, midwives, pharmacists and medical auxiliaries) as well as the establishments by specifying that in the event of an error in individual acts of prevention, diagnosis or care, they are responsible only if they made a prefessional mistake. Moreover, the establishments of health are responsible for the damage resulting from some infections, except if they bring back the proof of a foreign cause.
The L1142-2 article obliges the concerned professionals and establishments to subscribe an insurance to guarantee them for their civil or administrative liability, except for the publicly-owned establishments. Lastly, the L1142-3 to L1142-8 articles specify the cases where an error can carry out to a compensation and define a procedure of amicable settlement.

To sum up, put aside of the very particular cases, the professionals of health are protected in France, as long as they use recognized medical methods.

Blood transfusions
Another source of lawsuit against the doctors comes from the transfusions and the witnesses of Jéhovah, generally opposed to this practice : frequently, in many countries including France, that witnesses of Jéhovah carry complaint for having received a transfusion without their opinion.
It is also a source of dilemma for the professionals : the L1110-2 article of the code of the public health specifies that the sick person has the right to the respect of him dignity but the doctors are also subjected to the oath of Hippocrates which orders to them to save any person in danger.
Following a lawsuit of this type, the Council of State sliced by pronouncing an ordinance : the doctors don't seriously and obviously conflict with the fundamental freedom which the assent with a medical treatment given by a major patient constitutes, when after having very implemented to convince a patient to accept the essential care, they try to save him by an essential, survival and proportioned act (contentious n°249552, August 16, 2002)

Illegal exercise of medicine
The exercise of medicine is strictly reserved to the holders of a diploma. The illegal exercise is punished by the L378 article of the code of the public health. It can have several forms :
- going beyond of its competences by a true professional
- professionals of the beauty claiming to bring a cure (for example, the plastic surgery is reserved to the doctors)
- use of a false medical title
- practical of prohibited parallel medicines, such hypnosis without medical control or hypnotic passes. In these cases, the offence is marked whatever the result of the therapeutic act, even positive.

Medical secrecy
More than a basic right of any patient, the medical secrecy is a means of ensuring a confidence between patient and doctor. It is introduced in particular by the articles R4127-4, R4127-72 and R4127-73 of the code of the public health and applies to any professional of health, including for the occupational medicine. The article 10 of the civil code obliges any person to help the justice for the manifestation of the truth, except if there is a legitimate reason. The respect of the medical secrecy is usually regarded as legitimate reason.
However, if a patient uses the services of a dispensary or a mutualist group, medical information can circulate inside the organization. The medical secrecy can also be violated in some cases for minor patients. A patient can authorize his doctor to break the secrecy, for example to establish a medical certificate.

The question is very surging, more especially as it is very mediatized. Firstly, we have to distinguish the passive euthanasia (stop of the treatments in a desperate case - it is legal because it acts of a refusal of therapeutic eagerness) and the active euthanasia (in other words a suicide assisted by a third). A patient can refuse to receive care (passive euthanasia), in which case the doctor cannot be continued.
On the other hand, the active euthanasia is prohibited in France because it corresponds to several offences or crimes : voluntary or involuntary murder, not assistance to anybody in danger, provocation with the suicide... More precisely, if a patient asks for an euthanasia, the people which accept it can be condemned but the patient himself can't for two reasons : the suicide is legal and the different crimes (murder, not assistance to anybody in danger, ....) suppose an action on another person.