* French 2017 online sales 81.7 bln euros, up 14.3 pct
* Online sales could exceed 90 bln euros in 2018
* Lower average order value, higher purchase frequency
* 2017 sales generated through mobile phones up 38 pct
PARIS, Feb 6 (Reuters) - Online retail sales in France could exceed 90 billion euros ($112 billion) this year and top the 100 billion mark next year as the number of online vendors increases and people turn to the Internet and mobile phones to shop more often, the country's E-Commerce Federation (Fevad) said on Tuesday.
This would compare with a 14.3 percent year-on-year rise in 2017, when the French spent 81.7 billion euros buying online, the Fevad body said.
The 2017 numbers included Christmas sales of 16.5 billion euros, a 17.5 percent year-on-year increase.
Sales generated on web-based marketplaces rose 15 percent in 2017, while mobile sales increased by 38 percent.
For the seventh straight year, the average value of the basket of purchased goods declined, due to reduced or free shipping costs and the development of unlimited delivery subscriptions.
The average value of the basket fell 5 percent to 65.5 euros, although there was an increase in the frequency of purchases, Fevad said.
There were, on average, 33 online transactions per year per buyer in 2017, up from 28 in 2016.
Three of the most visited e-commerce websites in France are Amazon, CDiscount - owned by French retailer Casino - and book and CD retail chain Fnac-Darty.
In 2017, E-commerce represented 8.7 percent of overall French retail sales, up from against 7.7 percent in 2016.
($1 = 0.8030 euros) (Reporting by Dominique Vidalon Editing by Sudip Kar-Gupta)