Note 4. Intangible Assets


(in thousands of euros)	January 1, 2018	Increases	Decreases	December 31, 2018
Library of compounds	2,142	—	—	2,142
Software	1,398	106	—	1,504
Intangible assets, gross	3,540	106	—	3,646
Amortization of library of compounds	(828)	(165)	—	(993)
Amortization of software	(906)	(204)	—	(1,110)
Amortization	(1,733)	(369)	—	(2,103)
Intangible assets, net	1,806	(264)	—	1,543


(in thousands of euros)	January 1, 2019	Increases	Decreases	December 31, 2019
Library of compounds	2,142	—	—	2,142
Software	1,504	29	—	1,533
Intangible assets, gross	3,646	29	—	3,674
Amortization of library of compounds	(993)	(165)	—	(1,157)
Amortization of software	(1,110)	(179)	—	(1,289)
Amortization	(2,103)	(343)	—	(2,446)
Intangible assets, net	1,543	(314)	—	1,228


(in thousands of euros)	January 1, 2020	Increases	Decreases	December 31, 2020
Library of compounds	2,142	—	—	2,142
Software	1,533	0	—	1,533
Intangible assets, gross	3,674	0	—	3,674
Amortization of library of compounds	(1,157)	(165)	—	(1,322)
Amortization of software	(1,289)	(129)	—	(1,417)
Amortization	(2,446)	(293)	—	(2,739)
Intangible assets, net	1,228	(293)	—	935

Changes during the periods mainly correspond to amortization charges of €0.3 million by year.

In the absence of any indication of a loss of value, no impairment tests have been performed on amortizable intangible assets in the years ended December 31, 2018, 2019 and 2020.