[7] In January 1916 US nationals including Henry Clews Jr. who had booked to sail on Lafayette received anonymous letters warning them not to do so, as the Imperial German Navy would try to sink her.

[9] On the night of 20–21 August 1916 Lafayette accidentally rammed and sank Drifter, a 35 ft (11 m) private sloop, in the Ambrose Channel.

On 13 February Ateliers et Chantiers de la Gironde à Bordeaux started to convert her into a 1,400-bed hospital ship.

On 16 January 1919 she was at the Hook of Holland to embark sick or wounded French prisoners of war and repatriate them to Le Havre.

From the end of January she operated in the Mediterranean, calling at Ajaccio, Alexandretta, Bizerte, Corfu, Gravosa, Ragusa and Taranto.

She was carrying the Prime Minister of France, Aristide Briand,[17] who was on his way to head the French delegation to the Washington Naval Conference.

On 8 July 1922 Lafayette left Le Havre on a westbound crossing but that night was hit by a storm and heavy sea that tore off the hatch of her forward hold.

[18] In mid-Atlantic at 0130 hrs on 10 August 1922 the White Star liner RMS Adriatic suffered a gas explosion in her number three hold, which she was using as a reserve coal bunker.

Lafayette and the United States Lines liner Reliance changed course in response to Adriatic's distress message.

[19] In 1922, during the Prohibition era, US Attorney General Harry M. Daugherty declared that foreign-owned liners could not carry liquor in US territorial waters.

[20] CGT objected to the ban, insisted that it was enough for a ship to seal its bars and stop serving liquor to passengers before it reached the USA's three-mile limit.

[20] In 1928 CGT had the ship thoroughly refitted, renamed her Mexique[12] and transferred her to the routes to Mexico and Central America for which she had originally been built.

[21] CGT re-used the name Lafayette for a new 25,178 GRT motor ship that it had ordered for its route between Le Havre and New York, and which was launched in 1929.

[12] During the Battle of France on 2 June Mexique was in Marseille, and her anti-aircraft guns took part in the defence of the port against a German air raid.

On 19 June she arrived in the Gironde estuary to evacuate members of the National Assembly and take them to French North Africa.