A French couple have been accused of causing the death of their 13-month baby girl by putting anti-depressants and tranquillisers in her bottle to stop her from crying.

The parents, Delphine Niepceron, 27, and Cyrille Le Got, 43, from Champagne, just east of Le Mans, are standing trial at the Assize Court of Sarthe for "administration of harmful substance resulting in death without intention".

The tragedy occurred on the night of 27 February 2015 with the couple originally telling authorities that the child fell unconscious after she drank from a glass of rosé wine left by a guest, Le Parisien reported.

She was rushed to hospital in nearby Le Mans but the child, named Maëlyne, fell into a coma when and died at around 2.30am the next day, the court was told.

After the child's death a series of blood tests showed an unusually high concentration of anti-depressants and anxiolytics, that would usually be prescribed to adults suffering from depression, heard the court according to The Local, France.

Prosecutors said that the child could not yet walk, or drink from a glass, and that traces of the same drugs were found in the bottle of the couple's other daughter, Lena, who was three-years-old at the time.

Investigators said that they believe the parents administered the drugs to stop their children crying and to "calm" them so they would get off to sleep quicker.

Le Parisien reported that the investigators believe Le Got is an alcoholic who had suffered from cancer and that Niepceron was "immature".

The couple, who deny any wrongdoing, went on trial in Le Mans on Monday with a decision expected on Friday (15 December).

If convicted the pair, who deny the charges, face up to 20 years in prison.